Order Code RL34309

How Crime in the United States Is Measured

January 3, 2008

Nathan James
Analyst in Crime Policy
Domestic Social Policy Division
Logan Rishard Council
Intern
Domestic Social Policy Division

How Crime in the United States Is Measured
Summary
Crime data collected through the Uniform Crime Reports (UCR), the National
Incident-Based Reporting System (NIBRS), and the National Crime Victimization
Survey (NCVS) are used by Congress to inform policy decisions and allocate federal
criminal justice funding to states. As such, it is important to understand how each
program collects and reports crime data, and the limitations associated with the data.
This report reviews (1) the history of the UCR, the NIBRS, and the NCVS; (2)
the methods each program uses to collect crime data; and (3) the limitations of the
data collected by each program. The report then compares the similarities and
differences of UCR and NCVS data. It concludes by reviewing issues related to the
NIBRS and the NCVS.
The UCR represents the first effort to create a national, standardized measure
of the incidence of crime. It was conceived as a way to measure the effectiveness of
local law enforcement and to provide law enforcement with data that could be used
to help fight crime. UCR data are now used extensively by researchers, government
officials, and the media for research, policy, and planning purposes. The UCR also
provides some of the most commonly cited crime statistics in the United States. The
UCR reports offense and arrest data for 8 different Part I offenses and arrest data for
21 different Part II offenses.
The NIBRS was developed by the Federal Bureau of Investigation to respond
to the law enforcement community’s belief that the UCR needed to be updated to
provide more in-depth data to meet the needs of law enforcement into the 21st
century. The NIBRS collects data, including data on offense(s), offender(s),
victim(s), arrestee(s), and any property involved in an offense, for 46 different Group
A offenses and 11 different Group B offenses. Despite the more detailed crime data
that the NIBRS can provide, nationwide implementation of the program has been
slow, for a variety of reasons, including cost considerations.
The NCVS is the primary source of information on the characteristics of
criminal victimization, and on the number and types of crime not reported to law
enforcement. The NCVS has four major objectives: (1) to develop detailed
information about the victims and consequences of crime, (2) to estimate the number
and types of crimes not reported to police, (3) to provide uniform measures of
selected types of crimes, and (4) to permit comparisons over time and population
type (e.g., urban, suburban, and rural). The NCVS asks respondents whether they
have been the victim of rape and sexual assault, robbery, simple and aggravated
assault, purse snatching/pickpocketing, burglary, theft, or motor vehicle theft. In
addition to collecting data on the number of victimizations, the NCVS gathers data
on the details of each incident of victimization. This report will be updated as
warranted.

Contents
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Uniform Crime Reports (UCR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
UCR’s History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
How UCR Data Are Collected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
UCR Participation in the United States . . . . . . . . . . . . . . . . . . . . . . . . . 5
State UCR Programs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
UCR Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Scoring and Classifying UCR Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Development of the NIBRS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
The NIBRS Compared with the UCR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
NIBRS Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
NIBRS Certification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Classifying and Scoring NIBRS Data . . . . . . . . . . . . . . . . . . . . . . . . . 15
Advantages of the NIBRS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Transition to the NIBRS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Limitations of UCR and NIBRS Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Limited Offense Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Unreported Crimes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Reporting Practices of Law Enforcement . . . . . . . . . . . . . . . . . . . . . . 18
Missing Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Imputation Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
National Crime Victimization Survey (NCVS) . . . . . . . . . . . . . . . . . . . . . . . . . . 21
NCVS’ History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
How NCVS Data Are Collected . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
NCVS Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
NCVS Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Limitations of NCVS Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Sampling and Non-sampling Error . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Sampling Bias . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Series Victimizations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Changes in Household Residents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Limitations on the Scope of Crimes Covered . . . . . . . . . . . . . . . . . . . 35
Survey Design and Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
The UCR Compared with the NCVS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37
Select Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Implementing the NIBRS Nationwide . . . . . . . . . . . . . . . . . . . . . . . . . 39
Does the NIBRS Increase the Crime Rate? . . . . . . . . . . . . . . . . . . . . . 41
Decreases in the NCVS Sample Size . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Appendix A. Status of UCR and NIBRS Reporting, by State . . . . . . . . . . . . . . . 45
Appendix B. UCR Part I and Part II Offenses . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
Appendix C. UCR Hierarchy of Part I Offenses . . . . . . . . . . . . . . . . . . . . . . . . . 48

Appendix D. NIBRS Data Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Appendix E. Relationship Between NIBRS Data Elements . . . . . . . . . . . . . . . . 51
Appendix F. NIBRS Group A and Group B Offenses . . . . . . . . . . . . . . . . . . . . . 52
Appendix G. UCR Offense Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Appendix H. NIBRS Offense Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Appendix I. Number of Households and Persons Interviewed for the NCVS, by Year
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

List of Figures
Figure 1. Percentage of Victimizations Reported as Series Victimizations, 2000-2005
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

List of Tables
Table 1. Number and Percentage of Cases in Which NIBRS Crime Rates Differ from
UCR Crime Rates by 5.5% or Less . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

How Crime in the United States Is Measured
Introduction
Congress uses data from the Uniform Crime Reports (UCR), the National
Incident-Based Reporting System (NIBRS),1 and the National Crime Victimization
Survey (NCVS) to inform policy decisions and develop appropriate responses to
crime. Such crime data have been used to shape policy in a variety of ways. For
example, in the 103rd Congress, the Community Oriented Policing Services (COPS)
program was created to provide state and local law enforcement agencies with grants
to help them hire, rehire, and redeploy law enforcement officers to engage in
community policing. Congress cited both UCR and NCVS crime statistics when
articulating the need for more community policing officers.2
In addition to shaping policy, Congress has used crime data to develop formula
allocations for certain grant programs. For example, the Edward Byrne Memorial
Justice Assistance Grant (JAG) program formula uses UCR data to allocate federal
funds to state and local governments for criminal justice programs.3
In the 110th Congress, two bills have been introduced (S. 368 and H.R. 1700)
that would increase authorized funding for and expand the scope of the COPS
program.4 The impetus for the legislation was a recent increase in the violent crime
rate as reported by the UCR.5 Moreover, both the House and Senate Appropriations

1

Currently, there are not enough law enforcement agencies in the country submitting NIBRS
data for the Federal Bureau of Investigation (FBI) to report annual crime statistics using
NIBRS data. The FBI still publishes annual crime data using the UCR summary format (see
below). As such, the FBI converts data submitted from NIBRS-compliant law enforcement
agencies into UCR summary data.

2

U.S. Congress, Conference Committees, Violent Crime Control and Law Enforcement Act
of 1994, conference report to accompany H.R. 3355, 103rd Cong., 2nd sess., H.Rept. 103-711
(Washington: GPO, 1994), p. 372.

3

For more information on how UCR crime data are used in the JAG program, see CRS
Report RS22416, Edward Byrne Memorial Justice Assistance Grant Program: Legislative
and Funding History, by Nathan James.
4

For more information on S. 368, H.R. 1700, and the COPS program, see CRS Report
RL33308, Community Oriented Policing Services (COPS): Background, Legislation, and
Issues, by Nathan James.

5

U.S. Congress, House Committee on the Judiciary, COPS Improvement Act of 2007, report
to accompany H.R. 1700, 110th Cong., 1st sess., H.Rept. 110-150 (Washington: GPO, 2007),
pp. 6-7; U.S. Congress, Senate Committee on the Judiciary, COPS Improvement Act of 2007,
report to accompany S. 368, 110th Cong., 1st sess., S.Rept. 110-73 (Washington: GPO, 2007),
(continued...)

CRS-2
Committees recommended increased funding for state and local law enforcement to
support efforts to fight and prevent crime. The House report that accompanied the
House Commerce, Justice, and Science appropriations bill stated that the committee
was concerned about the recent increase in the violent crime rate.6 In addition, the
House and the Senate Appropriations Committees increased funding for the Federal
Bureau of Investigation (FBI) to hire additional agents to investigate violent crime.7
The committees felt it was important for the FBI to help state and local law
enforcement investigate violent crime in light of the recent increase in the violent
crime rate.8 The aforementioned legislation and congressional action were based on
crime data collected by the UCR and the NCVS.
Because of the importance of crime data in both shaping policy and allocating
federal funding, it is important to understand how each program collects data and the
limitations of the data. This report reviews (1) the history of the UCR, the NIBRS,
and the NCVS; (2) the methods each program uses to collect crime data; and (3) the
limitations of the data collected by each program. The report then compares the
similarities and differences of UCR and NCVS data. It concludes by reviewing
issues related to the NIBRS and the NCVS.

Uniform Crime Reports
When the UCR was established in the late 1920s, it represented the first
national, standardized measure of the incidence of crime. It was originally conceived
as a way to measure the effectiveness of local law enforcement to provide law
enforcement with data that could be used to help fight crime. UCR data are now
used extensively by academics and government officials for research, policy, and
planning purposes, and the data are widely cited in the media. The UCR also
provides some of the most commonly cited crime statistics in the United States. An
effort is currently underway to replace the UCR with the NIBRS, a more detailed
version of the UCR. However, the transition from the UCR to the NIBRS has been
slow.

5

(...continued)
pp. 3, 7.

6

U.S. Congress, House Committee on Appropriations, Subcommittee on Commerce, Justice,
Science, and Related Agencies, Making appropriations for the Departments of Commerce
and Justice, and Science, and Related Agencies for the fiscal year ending September 30,
2008, and for other purposes, report to accompany H.R. 3093, 110th Cong., 1st sess., H.Rept.
110-240 (Washington: GPO, 2007), p. 37.

7

Ibid., pp. 53-54; U.S. Congress, Senate Committee on Appropriations, Subcommittee on
Commerce, Justice, Science, and Related Agencies, Departments of Commerce and Justice,
Science, and Related Agencies Appropriations Act, 2008, report to accompany S. 1745, 110th
Cong., 1st sess., S.Rept. 110-124 (Washington: GPO, 2007), pp. 65-66.
8

Ibid.

CRS-3

UCR’s History
In 1927, the International Association of Chiefs of Police (IACP) formed the
Committee on Uniform Crime Records (the Committee) to develop a system for
collecting uniform crime statistics.9 The IACP felt that a national system of crime
reporting would put inevitable (and unpredictable) swings in the number of reported
crimes in a single jurisdiction into a proper context.10 The IACP felt that putting
changes in local crime incidence in the proper context would help reduce media
pressure on local jurisdictions and police chiefs from sensational or sporadic
increases in crime, which had resulted in some police departments “cooking the
books” to reduce the amount of recorded crime (though there was no reduction in the
amount of crime reported to the police).11 The Committee decided that offenses
known to police would be the most appropriate measure of the incidence of crime in
the United States.12 The Committee — after evaluating various crimes on the basis
of their seriousness, frequency of occurrence, pervasiveness in all areas of the
country, and likelihood of being reported to the police — identified seven crimes for
which local law enforcement would report data to the national program: felonious
murder, rape, robbery, aggravated assault, burglary, larceny/theft, and auto theft.13
The IACP focused on these seven crimes because they were prevalent, generally
serious in their nature, widely identified by victims and witnesses as criminal
incidents, and most likely to be reported to police.14 Differences in the way that state
criminal codes defined different crimes prevented the IACP from simply aggregating
state statistics to count the number of offenses known to police.15 Thus, the IACP
developed standardized offense definitions for the seven offense categories.
In 1929, IACP published Uniform Crime Reporting, a manual for police records
and statistics, which included uniform definitions for law enforcement agencies to
use when submitting data to IACP.16 In that same year, 400 cities in 43 states and the
territories of Puerto Rico, Hawaii, and Alaska submitted statistics to IACP, which
published the data in Uniform Crime Reports for the United States and Its

9

U.S. Department of Justice, Federal Bureau of Investigation, Uniform Crime Reporting
Handbook, Revised 2004, p. 2, hereafter “UCR Handbook.”
10

Michael D. Maltz, Bridging Gaps in Police Crime Data, NCJ 176365, September 1999,
U.S. Department of Justice, Office of Justice Programs, Bureau of Justice Statistics, p. 4,
hereafter “M.D. Maltz, Bridging Gaps in Police Crime Data.”
11

Ibid.

12

UCR Handbook, p. 2.

13

Ibid.

14

Clayton J. Mosher, Terance D. Miethe, and Dretha M. Phillips, The Mismeasure of Crime
(Thousand Oaks, CA: Sage Publications, 2002), p. 60, hereafter “C.J. Mosher et al., The
Mismeasure of Crime.”
15

Ibid.

16

Ibid.

CRS-4
Possessions.17 In 1930, Congress, at the urging of IACP, authorized the Attorney
General to collect crime data.18 The Attorney General designated the FBI as the
clearinghouse for crime data collected through the UCR.19
The scope of the UCR program has continued to expand since it was created.
Some of the changes to the UCR program include the following:
!

Starting in 1952, law enforcement agencies began to submit data on
the age, sex, and race of people arrested for crimes.20

!

Beginning in 1958, the FBI began to estimate annual crime rates for
the nation as a whole.21 Prior to 1958, the FBI did not aggregate the
data to the national level because there were not enough law
enforcement agencies submitting data to the FBI to allow it to report
national crime rates. Instead, the FBI published data in tables only
according to the size of the reporting jurisdiction.

!

In 1958, the FBI created a national crime index to serve as a general
indicator of criminality in the United States.22 The national crime
index was the total number of reported murder, rape, robbery,
aggravated assault, burglary, larceny/theft (over $50), and auto theft
offenses.23

!

In 1960, the UCR started to collect national statistics on law
enforcement officers killed.24 In 1972, the UCR started to collect
specific information on incidents in which law enforcement officers
were killed or assaulted.25

!

In 1962, the UCR, through the Supplementary Homicide Report
(SHR), started to collect data, where available, on the age, sex, and
race of murder victims, the weapon used, and the circumstances
surrounding the offense.

17

Ibid.

18

28 U.S.C. § 534.

19

UCR Handbook, p. 2.

20

Ibid.

21

M.D. Maltz, Bridging Gaps in Police Crime Data, p. 4.

22

UCR Handbook, p. 2.

23

Ibid.

24

Ibid.

25

Ibid.

CRS-5
!

In the late 1960s and throughout the 1970s, there was continued
growth of state UCR programs, which served as an intermediary
between local law enforcement and the FBI (see below).26

!

In 1978, Congress mandated the collection of arson data.27 In 1982,
Congress required the FBI to permanently count arson as a Part I
offense (a definition of “Part I offense” is below).28 The FBI started
to publish a “modified crime index,” which included the total
number of reported index crimes plus the total number of reported
arsons.

!

In 1990, following the passage of the Hate Crime Statistics Act (P.L.
101-275),29 the FBI started to collect data on bias motivation in
criminal incidents in which the offense resulted in whole or in part
because of the offender’s prejudice against a race, religion, sexual
orientation, or ethnicity/nationality.30 In 1994, Congress amended
the Act to require the FBI to collect data on incidents in which the
offense resulted from the offender’s bias against a physical or mental
disability.31

!

In 2004, the FBI discontinued publishing both the crime index and
the modified crime index. Since 2004, the FBI has published only
a violent crime total and a property crime total.32

How UCR Data Are Collected
UCR Participation in the United States. According to the FBI, 17,456
law enforcement agencies in the United States submitted UCR data in 2005, meaning

26

C.J. Mosher et al., The Mismeasure of Crime, p. 61.

27

UCR Handbook, p. 2.

28

Ibid.

29

For more information on the Hate Crime Statistics Act, see CRS Report RL33403, Hate
Crime Legislation, by William J. Krouse.
30

UCR Handbook, p. 3.

31

Ibid.

32

The FBI reported that it chose to suspend using the crime index and the modified crime
index after studying their appropriateness and usefulness for several years. The FBI
determined that both indexes were not true indicators of the degree of criminality because
they were driven upward by the offense with the highest number, typically larceny-theft. The
FBI reported that the sheer volume of those offenses overshadowed more serious but less
frequently committed offenses, creating a bias against a jurisdiction with a high number of
larceny-thefts but a low number of other serious crimes such as murder and forcible rape.
U.S. Department of Justice, Federal Bureau of Investigation, Crime in the United States,
2005: About CUIS 2005, September 2006, hereafter “About CUIS 2005.”

CRS-6
that 98%33 of all agencies in the nation participated in the UCR in 2005.34 Currently,
46 states and the District of Columbia submit UCR data through a state UCR
program (see Appendix A). In the remaining four states, local law enforcement
agencies submit UCR data directly to the FBI. In 25 of the states with a state UCR
program, law enforcement agencies are required by the state to submit UCR data to
the state program (see Appendix A).
State UCR Programs. In order for UCR data to be collected from law
enforcement agencies and submitted to the FBI, the state UCR programs must meet
certain requirements. The FBI established these requirements to ensure consistency
and comparability in the data it receives from state UCR programs.35 The FBI has
stated that should circumstances develop whereby a state UCR program does not
comply with the requirements, the FBI might bypass the state program and collect
UCR data directly from law enforcement agencies in the state.36 The FBI’s
requirements for state UCR programs are as follows:
!

The state UCR program must conform to national UCR program
standards, definitions, and information required.

!

The agency responsible for collecting UCR data must have a proven,
effective, statewide program, and it must have instituted acceptable
quality control procedures.

!

The state crime reporting must cover a percentage of the state’s
population at least equal to that covered by the national UCR
program.

!

The state UCR program must have adequate field staff assigned to
conduct audits and assist contributing agencies in record-keeping
practices and crime-reporting procedures.

!

The state UCR program must regularly provide the FBI with all of
the detailed data collected from individual law enforcement agencies
that report to the state UCR program in the form of duplicate returns,
computer printouts, and/or appropriate electronic media.

33

The Bureau of Justice Statistics reported that in 2004 there were 17,876 state and local
law enforcement agencies in the United States. U.S. Department of Justice, Office of Justice
Programs, Bureau of Justice Statistics, Law Enforcement Statistics. Document on file with
author, available upon request.
34

About CUIS 2005.

35

UCR Handbook, p. 4.

36

Ibid.

CRS-7
!

The state UCR program must have the proven capability (tested over
a period of time) to supply all the statistical data required in time to
meet the publication deadlines of the national UCR program.37

The FBI helps state UCR programs meet these requirements by (1) reviewing
and editing data submitted by individual agencies; (2) contacting individual agencies
within a state when necessary in connection with crime reporting matters; (3)
coordinating with the state UCR program to conduct training on law enforcement
record-keeping and crime-reporting procedures; (4) sending reporting forms to state
UCR programs so they can be distributed to law enforcement agencies within the
state; and (5) coordinating individual law enforcement agency contacts with the state
UCR program.38 The FBI also makes Quality Assurance Reviews (QARs) available
to state UCR programs. QARs are voluntary and part of the FBI’s triennial audit of
states’ criminal justice information systems.39 QARs help ensure that each state UCR
program adheres to summary and incident-based (see discussion of the NIBRS
below) reporting methods that are consistent with UCR standards, thereby increasing
uniformity in the data reported.40
UCR Data. The FBI collects data on the number of offenses known to police,
the number and characteristics of persons arrested, and the number of “clearances”41
for eight different offenses (see Appendix B), collectively referred to as Part I
offenses. Part I offenses include murder and nonnegligent manslaughter, forcible
rape, robbery, aggravated assault, burglary, larceny-theft, motor vehicle theft, and
arson. The FBI collects data on the number of arrests made for 21 other offenses (see
Appendix B), known as Part II offenses. The UCR is a summary system, meaning
that offense data submitted to the FBI by local law enforcement agencies show the
total number of known Part I offenses. Likewise, UCR arrest data show the total
number of persons arrested by reporting law enforcement agencies. Arrest data
37

Ibid.

38

Ibid.

39

Ibid., p. 3.

40

Ibid.

41

A “clearance” is when a known offense is “solved” through either an arrest or through
exceptional means. An offense is cleared through an arrest when at least one person is (1)
arrested, (2) charged with the commission of the offense, and (3) turned over to the court
for prosecution. In some cases, law enforcement cannot follow the three steps to clear an
offense by arrest. In these cases, law enforcement might be able to clear an arrest through
exceptional means. An offense is cleared through exceptional means when a law
enforcement agency can answer all of the following questions in the affirmative:
!
!
!
!

Has the investigation definitively established the identity of the offender?
Is there enough information to support an arrest, charge, and turning over
to the court for prosecution?
Is the exact location of the offender known so that the subject could be
taken into custody now?
Is there some reason outside the law enforcement control that precludes
arresting, charging, and prosecuting the offender? UCR handbook, p. 7882.

CRS-8
submitted to the UCR program by local law enforcement agencies also provide data
on the basic characteristics — age, sex, and race — of persons arrested.42 Because
the UCR is a summary system, there is no way to determine whether a particular
offense was cleared by an arrest, or whether an arrest was made pursuant to a certain
offense.
In addition to offense and arrest data, the FBI collects supplemental data on the
type and value of property stolen and recovered pursuant to reported crimes.43 The
FBI asks law enforcement agencies across the country to submit data to the UCR
program on the number of sworn officers and civilian law enforcement personnel.44
The FBI, through the UCR’s Supplementary Homicide Report (SHR), collects data
on the age, sex, and race of murder victims and offenders; the type of weapon(s) used
in the murders; relationships between victims and offenders; and the circumstances
surrounding each incident.45 The FBI collects data on incidents in which law
enforcement officers are killed, either feloniously or accidently, or assaulted while
performing their duties.46 The FBI also collects data on incidents of hate crime in the
United States. For each hate crime incident, law enforcement agencies collect data
on the offense type, location, bias motivation, victim type, number of offenders, and
the apparent race of the offenders.47
Law enforcement agencies submit offense, arrest, clearance, and SHR data
monthly. Law enforcement agencies submit data on law enforcement officers killed
or assaulted only when an officer has been killed or assaulted. The FBI requires law
enforcement agencies to submit hate crime data on a quarterly basis. The FBI
collects data on the number of sworn officers and law enforcement personnel
annually. The FBI publishes offense, arrest, clearance, SHR, and sworn law
enforcement officer data in its annual publication Crime in the United States. Data
on law enforcement officers killed or assaulted and on hate crimes are published by
the FBI in two separate publications: Law Enforcement Officers Killed or Assaulted
and Hate Crime Statistics.
Scoring and Classifying UCR Data. All law enforcement agencies
participating in the UCR system must classify and score reported crimes. Classifying
criminal offenses refers to the process of translating offense titles used in local and
state criminal codes into the standard UCR definitions for Part I and Part II
offenses.48 Scoring criminal offenses refers to counting the number of offenses after

42

Ibid., p. 96.

43

Ibid., p. 85.

44

About CUIS 2005.

45

Ibid.

46

U.S. Department of Justice, Federal Bureau of Investigation, Law Enforcement Officers
Killed or Assaulted, 2005.
47

U.S. Department of Justice, Federal Bureau of Investigation, Hate Crime Statistics, 2005.

48

C.J. Mosher et al., The Mismeasure of Crime, p. 63.

CRS-9
they have been classified.49 The FBI reminds state and local law enforcement
agencies that they must classify and score criminal offenses based on records for calls
for service, complaints, and/or investigations.50 According to the FBI, UCR data
must reflect offense counts, not the decision of a prosecutor or the findings of a court,
coroner, or jury.51 Uniformity in the classification and scoring of criminal offenses
across jurisdictions is essential for maintaining the integrity of UCR data.52 In
general, reporting law enforcement agencies classify and score attempted crimes as
though they were completed.53 For example, an attempt to steal a motor vehicle
would be classified and scored as a motor vehicle theft. The only exception to this
rule applies to attempted murder, which is classified and scored as aggravated
assault.54
The FBI has instituted three rules — the hierarchy, hotel, and separation of time
and place rules — that local law enforcement agencies must apply when they are
classifying and scoring criminal offenses. The hierarchy rule states that when
multiple Part I offenses occur in a single criminal incident, only the most serious
offense is scored and reported to the FBI.55 The hierarchy of Part I offenses is
provided in Appendix C. For example, if an offender raped and then murdered a
victim, the reporting law enforcement agency would score only the murder.
However, there are exceptions to the hierarchy rule. The hierarchy rule does not
apply to cases of arson, which are always scored and reported to the FBI, even if
other Part I offenses are committed during the incident.56 Another exception involves
motor vehicle theft. If a motor vehicle is stolen and, by extension, the contents of the
vehicle constitute a larceny-theft, only the motor vehicle theft is scored and reported
to the FBI, even though larceny-theft ranks higher on the hierarchy of Part I
offenses.57 The final exception to the hierarchy rule involves justifiable homicide.
In cases of justifiable homicide, two offenses are scored and reported: one for the

49

Ibid.

50

UCR Handbook, p. 7.

51

Ibid.

52

C.J. Mosher et al., The Mismeasure of Crime, p. 63.

53

UCR Handbook, pp. 15, 41.

54

Ibid.

55

The FBI states that the hierarchy rule applies only to crime reporting and does not affect
the number of charges for which a defendant may be prosecuted for in court. UCR
Handbook, p. 10.
56

If multiple Part I offenses are committed concurrently with the arson, the hierarchy rule
would be applied to the additional Part I offenses and only the most serious offense would
be scored along with the arson. Cynthia Barnett-Ryan, “Introduction to the Uniform Crime
Reporting Program,” in James P. Lynch and Lynn A. Addington, eds., Understanding Crime
Statistics: Revisiting the Divergence of the NCVS and UCR (New York: Cambridge
University Press, 2007), p. 65, hereafter “C. Barnett-Ryan, ‘Introduction to the UCR
Program.’”
57

Ibid.

CRS-10
felonious offense connected with the offender and one for the justifiable homicide,
which is reported as an unfounded58 murder/nonnegilgent manslaughter.59
The hotel rule applies only to burglary offenses. In cases where multiple
dwelling units under a single manager are burglarized and the offenses are more
likely to be reported to the police by the manager rather than the individual
occupants, the burglaries are scored as one offense.60 The hotel rule usually applies
to burglaries of hotels, motels, lodging houses, or other places where the lodging of
transients is the main purpose. The hotel rule would not apply in instances where
multiple units that were leased or rented to tennants were burglarized, such as
apartments or offices in a business building.61 For example, if five hotel rooms were
burglarized, it would be scored as one burglary, but if five apartments were
burglarized, it would be scored as five burglaries.
The separation of time and place rule applies in instances where the same
offender commits multiple offenses over a short period of time in different
locations.62 In such cases, the reporting agency treats the offenses as separate events
and classifies and scores them accordingly (i.e., applies the hierarchy and/or hotel
rule).63 According to the FBI, the “same time and place” means that the time interval
between the offenses and the distance between the locations where they occurred are
insignificant.64 Normally, the offenses must have occurred during an unbroken
period of time and at the same or adjoining location(s).65 However, the time and
place rule does not apply in instances where offenses, even if they are committed at
different times and places, are a part of continuing criminal activity committed by the
same offender(s), and an investigation deems the activity to constitute a single
criminal transaction.66
When scoring offenses, the UCR program distinguishes between crimes against
persons (i.e., homicide/nonnegligent manslaughter, rape, and aggravated assault) and
crimes against property (i.e., robbery, burglary, larceny-theft, motor vehicle theft, and
arson).67 For crimes against persons, one offense is counted for each victim in the

58

“Unfounded” crimes are crimes that come to the attention of law enforcement but are later
found to be false or baseless.
59

Ibid., pp. 65-66.

60

UCR Handbook, p. 62.

61

Ibid.

62

Ibid., p. 12.

63

C. Barnett-Ryan, “Introduction to the UCR Program,” p. 66.

64

UCR Handbook, p. 12.

65

Ibid.

66

Ibid.

67

Ibid, p. 41.

CRS-11
criminal incident.68 For example, if a gunman shot and killed three people, the
reporting agency would report three homicides. For crimes against property, one
offense is counted for each distinct operation or attempt in a criminal incident, with
the exception of motor vehicle theft, in which case one offense is counted for each
stolen vehicle and one offense for each attempt to steal a motor vehicle in a criminal
incident.69 For example, if someone walked into a store, pulled a gun, and robbed
five customers, it would be scored as one robbery. In instances where multiple Part
I offenses are committed against multiple victims in the same criminal incident, the
hierarchy rule is applied first, and then crimes are scored based on whether they were
crimes against persons or crimes against property. For example, if an assailant
robbed one person and murdered someone who tried to break up the robbery, only
the murder would be scored, even though two crimes were committed against two
different people in the same criminal incident.
In addition to classifying and scoring offense data, law enforcement agencies
must classify and score arrest data. In many ways, arrests are classified and scored
similar to the way offenses are classified and scored. Arrest data submitted to the
FBI reflect the number of people arrested, not the number of charges lodged.70 For
example, if one person is arrested for multiple crimes, the reporting law enforcement
agency reports one arrest. However, if one person is arrested multiple times, and
there is a separation of time and space between the arrests, each arrest is recorded
separately. If a person is arrested for multiple charges, the reporting agency must use
only one crime classification when reporting the arrest.71 Thus, if a person is arrested
for both Part I and Part II offenses, the reporting agency ignores the Part II offenses
and scores only the most serious Part I crime (see Appendix C) for which the person
was arrested. If a person is arrested for Part II offenses, the reporting agency must
determine which is the most serious offense and score an arrest only for that
offense.72 If multiple people are arrested for the same crime, each person is counted
as a separate arrest.73 If a reporting agency determines that someone in custody has
committed other crimes, the agency does not report additional arrests; it reports only
the original arrest.74

Development of the NIBRS
The data collected and disseminated by the UCR remained largely unchanged
over time (i.e., since the beginning of the UCR system in 1929). Starting in the
1970s, consensus grew in the law enforcement community that the UCR needed to
be updated to provide more in-depth data to meet the needs of law enforcement into

68

Ibid.

69

Ibid.

70

Ibid., p. 96.

71

Ibid., p. 97.

72

Ibid.

73

Ibid.

74

Ibid.

CRS-12
the 21st century.75 In response, the FBI, through the Bureau of Justice Statistics
(BJS), contracted for a phased study of the UCR program, which culminated with
recommendations on how it could be improved.76 The study’s final report, Blueprint
for the Future of the Uniform Crime Reporting Program (Blueprint), was released
in May 1985, and it outlined three areas where the UCR could be enhanced to meet
the future needs of law enforcement.77 The study recommended that law enforcement
agencies use an incident-based system to report offenses and arrests.78 It also
recommended that some law enforcement agencies submit incident-based data for all
of their known offenses and all arrests (i.e., full participation), while other law
enforcement agencies submit only a more limited range of incident-based data for
certain crimes (i.e., limited participation).79 The study also recommended that the
national UCR program implement a quality assurance program.80
Based on the recommendation outlined in the Blueprint, the FBI developed
guidelines and design specifications for what would later become the National
Incident-Based Reporting System (NIBRS).81 The FBI chose the South Carolina Law
Enforcement Division (SLED) to conduct a pilot study of the newly developed
NIBRS guidelines and design specifications.82 SLED adapted its existing incidentbased UCR system to meet NIBRS specifications, and it enlisted the assistance of
nine local law enforcement agencies in the state to participate in the pilot study.83

75

SEARCH, Cost Issues of Implementing the National-Incident Based Reporting System in
Local Law Enforcement Agencies, May 1997, hereafter “SEARCH, ‘Cost Issues of
Implementing NIBRS.’”
76

C. Barnett-Ryan, “Introduction to the UCR Program,” p. 81.

77

U.S. Department of Justice, Federal Bureau of Investigation, Crime in the United States
2005: About the UCR Program, September 2006, hereafter, “About the UCR Program
2005.”
78

Ibid.

79

The Blueprint initially proposed that only a small sample of law enforcement agencies
nationwide (3%-7%) would report comprehensive incident-based statistics. The remaining
law enforcement agencies would report incident-based data but in a much more abbreviated
format, focusing only on Part I UCR offenses, with a limited range of victim, offender, and
incident data. All law enforcement agencies would collect and submit arrest data, with
linkages to cleared offenses. U.S. Department of Justice, Office of Justice Programs,
Bureau of Justice Statistics, Implementing the National Incident-Based Reporting System:
A Project Status Report, NCJ 165581, July 1997, p. 5, hereafter “BJS, ‘Implementing
NIBRS Status Report.’”
80

Ibid.

81

U.S. Department of Justice, Federal Bureau of Investigation, National Incident-Based
Reporting System, Volume 1: Data Collection Guidelines, August 2000, p. 1, hereafter
“NIBRS Data Collection Guidelines.”
82

Ibid.

83

Ibid., p. 2.

CRS-13
The pilot study ran from March 1 to September 30, 1987, and it resulted in further
refinement of NIBRS’s guidelines and specifications.84
The FBI presented the NIBRS to law enforcement at a national UCR conference
in March 1988.85 The conference gave the FBI the opportunity to receive feedback
on the NIBRS from the law enforcement community.86 According to the FBI,
conference attendees overwhelmingly supported implementation of the NIBRS
nationwide.87 Attendees passed three overall recommendations: (1) that there be
established a new, incident-based national crime reporting system; (2) that the FBI
manage the program; and (3) that an advisory policy board composed of law
enforcement executives be formed to help direct and implement the new program.88
The law enforcement community rejected the Blueprint’s proposal to have both full
and limited participating law enforcement agencies, and endorsed implementing the
full version of the NIBRS nationwide.89

The NIBRS Compared with the UCR
NIBRS Data. As discussed above, under the UCR, local law enforcement
agencies tally the number of known offenses for each Part I offense, as well as arrest
data for both Part I and Part II offenses, and submit aggregate counts on a monthly
basis to the FBI. Under the NIBRS, data are not aggregated; rather, data for each
criminal incident90 are submitted to the FBI in a separate report.91 For each criminal
incident, participating law enforcement agencies collect data on 53 different data
elements, including data on the offense(s), the offender(s), the victim(s), the

84

Ibid.

85

Ibid.

86

Ibid.

87

Ibid.

88

About the UCR Program 2005.

89

C. Barnett-Ryan, “Introduction to the UCR Program,” p. 82.

90

An incident is defined for NIBRS reporting purposes as one or more offenses committed
by the same offender, or group of offenders “acting in concert,” at the “same time and
place.” “Acting in concert” requires that the offenders actually commit or assist in the
commission of the crime(s). The offenders must be aware of and consent to the commission
of the crime(s) or even if nonconsenting, their actions assist in the commission of the
offense(s). As it is under the UCR system, for the purposes of NIBRS reporting, “same time
and place” means that the time interval between the offenses and the distance between
locations where they occurred are insignificant. Normally, the offenses must have occurred
during an unbroken period of time and at the same or adjoining location(s). However, the
time and place rule does not apply in instances where offenses, even if they are committed
at different time and places, are a part of continuing criminal activity committed by the same
offender(s), and an investigation deems the activity to constitute a single criminal
transaction. NIBRS Data Collection Guidelines, pp.16-17.
91

Ibid., p. 5.

CRS-14
arrestee(s), and any property involved in the offense.92 The data elements are
combined into six different data segments (see Appendices D and E). The NIBRS
allows for data on multiple offenses, offenders, and victims to be collected for each
criminal incident.93
NIBRS data are intended to be a by-product of local incident-based reporting
(IBR) systems.94 Therefore, local and state law enforcement agencies can develop
their own IBR systems to suit their local needs, and they can use the data from their
own IBR systems to participate in the NIBRS, as long as the data submitted to the
FBI meets NIBRS specifications. State and local law enforcement agencies can add
additional data elements or data values to their systems.95
The NIBRS does not use the UCR’s Part I and Part II offense classifications.
Instead, offenses are classified as being either a Group A or Group B offense (see
Appendix F). Group A contains 46 different offenses grouped into 22 offense
categories. Group B contains 11 different offenses. Law enforcement agencies are
required to submit incident reports, which contain data from all six data segments,
for all Group A offenses.96 For Group B offenses, law enforcement agencies are
required to submit only arrest reports, which contain data only from the arrestee data
segment.97 The expanded list of crimes required the FBI to create definitions for
crimes counted only in the NIBRS and to modify definitions for crimes that are a part
of the UCR.98 For example, the FBI expanded the definition of rape to include rapes
of both women and men. Under the UCR, rapes are defined as being committed
against women only.
NIBRS Certification. Before a state can submit NIBRS data to the FBI, the
state NIBRS program must be certified by the FBI.99 The FBI has developed a state
certification policy, which uses the following criteria to evaluate the NIBRS data
submitted by a state:
!

92

Error rate — before a state can submit NIBRS data, the FBI requires
that fewer than 4% of the incident reports submitted by the state
contain errors for three consecutive months.

C.J. Mosher et al., The Mismeasure of Crime, p. 70.

93

Michael G. Maxfield, “The National Incident-Based Reporting System: Research and
Policy Applications,” Journal of Quantitative Criminology, vol. 15, no. 2 (1999), p. 123.
94

SEARCH, “Cost Issues of Implementing NIBRS,” p. 1.

95

Ibid.

96

NIBRS Data Collection Guidelines, p. 5.

97

Ibid., p. 8.

98

C. Barnett-Ryan, “Introduction to the UCR Program,” p. 62.

99

BJS, Implementing NIBRS Status Report, p. 7.

CRS-15
!

Statistical reasonableness — before a state can submit NIBRS data,
the FBI evaluates the reasonableness of the data based on analyses
of trends, volumes, and monthly fluctuations.

!

Updating capability and responsiveness — the FBI requires the state
program to have ample ability to update its records, meet deadlines,
and respond in a timely manner to error messages from the national
program.

!

System appropriateness — the FBI requires a state’s NIBRS
program to be systematically compatible with the NIBRS data
reporting requirements and guidelines.100

Simply because a state’s IBR program is certified as NIBRS-compliant does not
necessarily mean that every law enforcement agency in the state is reporting NIBRScompliant data.101 If a state’s program is certified by the FBI, it means that the state
program is capable of processing NIBRS data at the state level and submitting
virtually error-free data to the FBI in an acceptable format.102
If a state program is certified as NIBRS-compliant, local law enforcement
agencies within the state must submit their NIBRS data through the state program.103
If a state does not have a certified state program, the FBI will consider allowing local
law enforcement agencies with NIBRS-compliant IBR systems to submit data
directly to the FBI, if the agency serves a population of over 100,000.104 The FBI
coordinates decisions regarding such requests with the appropriate state UCR
program. If a local law enforcement agency in a state without a state UCR program
wants to submit NIBRS data directly to the FBI, it will consider such a request if the
agency has a NIBRS-compliant IBR system.105 The FBI reported that the number of
local law enforcement agencies in states without UCR programs allowed to submit
NIBRS data directly to the FBI is limited by the availability of resources at the FBI.106
When a local law enforcement agency is allowed to submit NIBRS data directly to
the FBI, the agency must sign an agreement stating that it will discontinue direct
reporting to the FBI when the state has a certified program.107
Classifying and Scoring NIBRS Data. Like the UCR program, law
enforcement agencies participating in the NIBRS have to classify and score offenses.
However, the NIBRS does not use the hierarchy rule discussed previously because

100

Ibid.

101

Ibid.

102

Ibid.

103

NIBRS Data Collection Guidelines, p. 4.

104

Ibid.

105

Ibid.

106

Ibid.

107

Ibid.

CRS-16
law enforcement agencies can report all of the offenses that occurred in a criminal
incident.108
The FBI expanded the definition of the hotel rule under NIBRS to apply to
rental storage facilities (i.e., mini-storage and self-storage buildings).109 For example,
10 storage units burglarized in one self-storage building would be counted as one
burglary offense. However, NIBRS data reporting allows law enforcement agencies
to report how many premises were entered (see Appendix D, data element 10 under
the Offense segment). Using the same example, the break-ins at the storage facility
would be reported as one burglary, even though the law enforcement agency would
include data in the incident report indicating that 10 premises were entered.
The separation of time and place rule still applies when classifying and scoring
offenses under the NIBRS.110 Law enforcement agencies have to use the separation
of time and place rule to determine whether a group of offenses should be reported
as individual incidents, or whether the offenses should be reported as one incident
where multiple offenses occurred.
Like the UCR program, the NIBRS also distinguishes between crimes against
persons and crimes against property. Crimes against persons and crimes against
property are scored the same way for NIBRS reporting as they are for UCR reporting.
However, because NIBRS Group A offenses include offenses that cannot be
classified as crimes against persons (because they do not involve an actual victim)
or classified as crimes against property (because property is not the object of the
crime), the NIBRS includes another scoring category — crimes against society.111
For NIBRS reporting, crimes against society include drug/narcotics offenses,
gambling offenses, pornography/obscene materials, and prostitution offenses (see
Appendix F). Reporting law enforcement agencies score one offense for each crime
against society in an incident.112
Advantages of the NIBRS. Because of the expanded amount of data
collected in NIBRS reporting, the NIBRS has several advantages compared with the
traditional UCR system. In addition to those described above, advantages of the
NIBRS include the following:
!

Data collection is not restricted to a limited number of offense
categories (i.e., Part I offenses).

!

Offense definitions can meet state, local, and national reporting
needs.

108

Ibid., p. 13.

109

Ibid., p. 15.

110

Ibid., pp.16-17.

111

Ibid., p. 14.

112

Ibid.

CRS-17
!

Details on individual crime incidents (offenses, offenders, victims,
property, and arrests) can be collected and analyzed.

!

Arrests and clearances can be linked to specific incidents and
offenses.

!

Distinctions can be made between attempted and completed crimes.

!

Linkages can be established between variables for examining
interrelationships between offenses, offenders, victims, property, and
arrestees.

!

Detailed crime analyses can be made within and across law
enforcement jurisdictions.

!

Strategic and tactical crime analyses can be made at the local and
regional levels.113

Transition to the NIBRS
According to the Justice Research and Statistics Association’s IBR Resource
Center, approximately 22% of the nation’s population is covered by law enforcement
agencies that report NIBRS-compliant data and 17% of reported crime is reported
through the NIBRS program.114 As of August 2007, and as shown in Appendix A,
31 states had been certified by the FBI to submit NIBRS data. In addition, the FBI
accepts NIBRS data directly from agencies in Alabama, Illinois, Kentucky, and the
District of Columbia, even though each state does not have an FBI-certified NIBRS
program. In 11 states (35% of all certified states), all law enforcement agencies in
the state collect and submit NIBRS-compliant data. In another 10 states (32% of all
certified states), between 50%-99% of law enforcement agencies in the state collect
and submit NIBRS-compliant data.

Limitations of UCR and NIBRS Data
Limited Offense Data. As discussed above, the UCR collects offense data
on a limited number of crimes (Part I crimes), which means that offense data are
available only for a small number of all crimes committed in the United States.
Offense data are not available for Part II crimes, which tend to be committed at a
greater frequency than Part I crimes. Currently, the UCR does not collect data on
crimes commonly covered by the media, such as kidnapping, bribery, or child
pornography. The FBI is trying to address this gap by implementing the NIBRS, but
as discussed above, many jurisdictions have yet to make the switch from the UCR to
113

Justice Research and Statistics Association, IBR Resource Center, Advantages of
Incident-Based Reporting Over Summary Reporting. Document on file with author,
available upon request.
114

Justice Research and Statistics Association, IBR Resource Center, Status of NIBRS in the
States, document on file with author, available upon request.

CRS-18
the NIBRS. Neither the UCR nor the NIBRS collect data on political crimes, pricefixing and illegal environmental pollution.115 Moreover, the UCR and the NIBRS
most likely undercount corporate and occupational crimes.116
Unreported Crimes. As discussed above, both the UCR and the NIBRS
collect data on the number of offenses known to law enforcement each year.
However, not all crimes that occur are known to the police. In some cases, the
victim(s) of or witness(es) to a crime might not report the incident to the police.117
Researchers have reported that a majority of crimes become known to the police only
after they are reported by either the victims or citizens who witnessed the crime.118
If crimes are not reported to law enforcement, both the UCR and NIBRS will
undercount the actual amount of crime that occurred.
Reporting Practices of Law Enforcement. Evidence shows that UCR
data may be affected by the reporting practices of local law enforcement. In some
instances, law enforcement officials, usually because of political pressure to lower
the crime rates, might manipulate crime reports to decrease the amount of reported
crime.119 In other instances, the number of reported offenses might be a product of
how assiduously local law enforcement follow the FBI’s definitions for crimes under
the UCR or the NIBRS.120 For example, if a local law enforcement agency does not
closely follow UCR or NIBRS definitions, the agency might classify an assault
against a woman as an attempted rape, or a trespass as a burglary. Ironically, the
number of reported offenses might increase as local law enforcement agencies
become more efficient.121 If a law enforcement agency puts more officers on patrol,
the number of known offenses might increase because there are more officers to
catch offenders. If law enforcement agencies work to develop a better relationship
with the citizens they serve, the reported number of offenses could increase because
citizens might report more crimes. The number of reported offenses might also
increase as law enforcement agencies develop better record-keeping systems and as

115

C.J. Mosher et al., The Mismeasure of Crime, p. 86.

116

Ibid.

117

2005 NCVS data showed that 57.4% of all crimes, 51.3% of personal crimes, 50.7% of
crimes of violence, and 59.3% of property crimes were not reported to police. U.S.
Department of Justice, Office of Justice Programs, Bureau of Justice Statistics, Criminal
Victimization in the United States, 2005 Statistical Tables, National Crime Victimization
Survey, Table 91, NCJ 215244, December 2006, p. 107.

118

C.J. Mosher et al., The Mismeasure of Crime, p. 84.

119

David Seidman and Michael Couzens, “Getting the Crime Rate Down: Political Pressures
and Crime Reporting,” Law and Society Review, vol. 8 (1973-1974), p. 457; Larry J. Siegel,
Criminology (9th ed.) (Belmont, CA: Thompson and Wadsworth, 2006), p. 35, hereafter,
“L.J. Seigel, Criminology”; C.J. Mosher et al., The Mismeasure of Crime, pp. 91-93.

120

L.J. Siegel, Criminology, p. 35.

121

Ibid.

CRS-19
they assign more employees to do dispatching, record keeping, and criminal incident
reporting.122
Missing Data. Federal law does not require local law enforcement agencies
to submit offense data to the UCR program. Although participation in the UCR
program has been above 90% since the 1970s, not all law enforcement agencies in
the country submit UCR data to the FBI.123 Also, law enforcement agencies are not
required to submit a full year of UCR data to the FBI.124 In some instances, a local
law enforcement agency will submit only a few months’ worth of data, or will fall
shy of the full 12 months by 1 or 2 months.125 In other instances, a local law
enforcement agency will submit offense data but will not submit any of the other data
(e.g., the supplementary homicide report data or the hate crime data; see discussion
above).126
One researcher found that missing data are not equally distributed among all law
enforcement agencies in the country. The researcher reported that, for the years
1960-2003, law enforcement agencies serving populations under 2,500 people and
university and college law enforcement agencies are more likely to have missing data
than law enforcement agencies that serve populations over 2,500 people.127 In
general, the larger the population the law enforcement agency served, the less likely
the agency was to have missing data. The analysis showed that law enforcement
agencies that served 250,000 or more people did not have missing data for the years
1960-2003.128
Imputation Procedures. If a law enforcement agency does not report UCR
data to the FBI for the entire year, the FBI uses imputation techniques to estimate the
law enforcement agency’s number of reported crimes for the entire year.129 The
methodology differs depending on the number of months for which crime data were
reported. If the law enforcement agency has submitted three or more months of data,
the FBI estimates the total annual number of crimes for the jurisdiction by
multiplying the reported number of crimes by a weight equal to “12/N,” where “N”

122

Ibid.

123

C.J. Mosher et al., The Mismeasure of Crime, p. 88.

124

C. Barnett-Ryan, “Introduction to the UCR Program,” p. 69.

125

Ibid.

126

Ibid.

127

Michael D. Maltz, Analysis of Missingness in UCR Crime Data, U.S. Department of
Justice, Office of Justice Programs, August 2006, p. 11.

128
129

Ibid., p. 12.

The FBI converts all NIBRS data into summary UCR data for publication in Crime in the
United States. If a law enforcement agency reports NIBRS data and does not report any data
for the year, or if it reports data only for part of the year, the FBI converts the reported data,
if any, to summary UCR data. The FBI then applies the imputation procedures used for
summary UCR data to estimate the agency’s crime rate for the full year.

CRS-20
equals the number of months of data submitted by the law enforcement agency.130
For law enforcement agencies that have submitted less than three months of data
(“non-reporting agencies”), the missing data are estimated based on the reported
number of crimes from other similar agencies based on population. For core cities
in a Metropolitan Statistical Area (MSA),131 the crime rate is estimated by applying
the crime rate for all other law enforcement agencies in the agency’s population
group132 to the agency’s population.133 For example, if a law enforcement agency
served a city of 80,000 people and the murder rate for all other MSA core cities in
its population group was 10 per 100,000, then the estimated number of murders for
the city would be 8 (calculated as 80,000x10.0/100,000). The crime rates for the
remaining agencies are estimated using the state rate for the agency’s population
group from the current year.134 In absence of a state rate, the FBI will apply the
division135 or region136 rate. Agency-level estimates are always aggregated into larger
geographic areas, such as MSAs, state, geographic division, region, and the nation.137
Researchers have stated that the imputation methods used by the FBI to estimate
crime in jurisdictions that have not reported for the full year or non-reporting
jurisdictions make questionable assumptions. The imputation method used by the
FBI to estimate a full year’s worth of data for jurisdictions that report three or more
months of data implicitly assumes that the crime rate for non-reported months is the

130

M.D. Maltz, Bridging Gaps in Police Crime Data, p. 23; C. Barnett-Ryan, “Introduction
to the UCR Program,” p. 70.
131

MSA is a designated area consisting of a principal city of at least 50,000 people and the
surrounding counties that have strong economic ties.
132

The FBI classifies each law enforcement agency into one of eight population groups. The
population groups are as follows: I (250,000 inhabitants or more); II (100,000-249,999
inhabitants); III (50,000-99,999 inhabitants); IV (25,000-49,999 inhabitants); V (10,00024,999 inhabitants); VI (less than 10,000 inhabitants; includes universities and colleges to
which no population is attributed); VIII (Nonmetropolitan county; includes state police to
which no population is attributed); and IX (Metropolitan county; includes state police to
which no population is attributed). About CUIS 2005.
133

The FBI attempts to collect data from core cities for the full year in order to avoid
estimating crime data for the city. C. Barnett-Ryan, “Introduction to the UCR Program,” p.
70.
134

Ibid.

135

Geographic divisions are as follows: Pacific (AK, HI, WA, OR, and CA); Mountain (MT,
UT, ID, AZ, NM, NV, WY, and CO); West North Central (ND, SD, MN, NE, KS, IA, and
MO); West South Central (OK, TX, AR, and LA); East North Central (WI, MI, IL, IN, and
OH); East South Central (KY, TN, AL, and MS); South Atlantic (DE, MD, WV, VA, NC,
SC, GA, and FL); Middle Atlantic (NY, PA, and NJ); and New England (CT, RI, MA, VT,
NH, and ME). About CUIS 2005.
136

The geographic regions are as follows: West (AK, HI, WA, OR, CA, MT, UT, ID, AZ,
NM, NV, WY, and CO); South (OK, TX, AR, LA, KY, TN, AL, MS, DE, MD, WV, VA,
NC, SC, GA, and FL); Midwest (ND, SD, MN, NE, KS, IA, MO, WI, MI, IL, IN, and OH);
and Northeast (NY, PA, NJ, CT, RI, MA, VT, NH, and ME). About CUIS 2005.
137

C. Barnett-Ryan, “Introduction to the UCR Program,” p. 71.

CRS-21
same as for reported months.138 If the crime rates in the months for which data were
not reported differ from the rates in the months for which data were reported, then
the imputation procedure could either overestimate or underestimate the
jurisdiction’s annual crime rate. The imputation procedure used to estimate the crime
rate for non-reporting jurisdictions assumes that cities and towns with similar sized
populations are also similar in other factors that might affect the city or town’s crime
rate, such as income distribution, unemployment rates, population density, and racial
composition.139

National Crime Victimization Survey
The National Crime Victimization Survey (NCVS) is the primary source for
information on the characteristics of criminal victimization and on the number and
types of crime not reported to law enforcement.140 The NCVS has four major
objectives: (1) developing detailed information about the victims and consequences
of crime, (2) estimating the number and types of crimes not reported to police, (3)
providing uniform measures of selected types of crimes, and (4) permitting
comparisons over time and population types (e.g., urban, suburban, and rural).141

NCVS’s History
The NCVS began as a way to supplement UCR data.142 In 1965, President
Lyndon Johnson convened the President’s Commission on Law Enforcement and the
Administration of Justice (hereafter referred to as “the Commission”).143 The
Commission was charged with examining the causes and characteristics of crime in
the United States and formulating recommendations for polices and programs that
could address crime in the country.144 At the time, the UCR was the only source for
official crime data, and the Commission found that several limitations145 associated
138

C.J. Mosher et al., The Mismeasure of Crime, p. 89.

139

Ibid., p. 90.

140

U.S. Department of Justice, The Nation’s Two Crime Measures, NCJ 122705, October
2004, p. 1, hereafter “U.S. DOJ, The Nation’s Two Crime Measures.”
141

National Archive of Criminal Justice Data, National Crime Victimization Survey
Resource Guide. Document on file with author, available upon request.

142

Callie Marie Rennison and Michael Rand, “Introduction to the National Crime
Victimization Survey,” in James P. Lynch and Lynn A. Addington, eds., Understanding
Crime Statistics: Revisiting the Divergence of the NCVS and UCR (New York: Cambridge
University Press, 2007), p. 19, hereafter “C.M. Rennison and M. Rand, ‘Introduction to the
NCVS.’”

143

Ibid., p. 18.

144

Ibid.

145

The Commission found four limitations associated with UCR data that prevented it from
addressing the needs of the Commission. The Commission found that UCR data
(continued...)

CRS-22
with the data prevented it from helping the Commission develop policy
recommendations.146 To help rectify some of the limitations associated with UCR
data, the Commission recommended the creation of a national survey of crime
victimization.147
The first crime victimization survey pilot study was conducted in three
Washington, D.C., police precincts in the spring of 1966.148 The survey asked 511
Washington, D.C., residents, chosen from a probability sample of homes, whether
they had been a victim of one or more of a list of crimes.149 The Washington, D.C.,
pilot study demonstrated that household surveys could provide a different picture of
crime than the one derived from UCR data. The study showed that, depending on the
type of crime, there were 3 to 10 times as many criminal incidents reported by
victims than there were recorded in UCR data.150
A supplementary study was conducted in three cities: Boston, Chicago, and
Washington, D.C. The second study surveyed businesses and organizations in
selected high-crime areas of all three cities about criminal victimizations they had
experienced.151 The supplementary study also surveyed residents of Chicago and
Boston about their household’s criminal victimizations.152 Like the Washington,
D.C., pilot study, the supplementary study found that the number of reported
victimizations exceeded the number of reported crimes.153
A third victimization survey sponsored by the Commission was conducted by
the National Opinion Research Center (NORC).154 NORC’s victimization survey
differed from the two previous surveys in that it involved a national sample, not just
a sample of local households and businesses. NORC’s victimization survey

145

(...continued)
! reflected only crimes known to law enforcement;
! reflected law enforcement activity and not necessarily actual crime trends;
! were open to possible manipulation and misrepresentation that could
threaten their validity; and
! lacked important information about the criminal incident, including details
about the characteristics of offenders, offenses, and victims. (Ibid., pp.
18-19.)

146

Ibid.

147

Ibid., p. 19.

148

C.J. Mosher et al., The Mismeasure of Crime, p. 54.

149

Ibid.

150

Ibid.

151

Ibid., pp. 54-55.

152

Ibid., p. 55.

153

Ibid.

154

Ibid.

CRS-23
interviewed one person in each of 10,000 households nationwide.155 Like the two
previous pilot studies, NORC’s survey found that more crime was being committed
than was being reported to law enforcement.156 Unlike the other two studies,
NORC’s survey collected data on which crimes were not reported to the police and
on the respondent’s reason for not reporting the crime. Non-reporting was found to
vary by offense. For example, the study found that 90% of consumer frauds were not
reported, but 11% of motor vehicle thefts were unreported.157 NORC found that most
people who chose not to report a crime to the police did so because they either
thought the incident was a private matter or did not think the police could do
anything about it.158
The three pilot studies indicated that UCR data underestimated the true level of
crime in the United States. Moreover, the studies showed that a household survey
could help estimate the extent of unreported crime, also known as the “dark figure
of crime.”159 They also demonstrated that a household survey was a reasonable
method for estimating the number of criminal victimizations in the United States.160
The Commission recommended that a national criminal justice statistics center be
established to collect victimization data on an ongoing basis.161 In 1968, the Law
Enforcement Assistance Administration (LEAA)162 was created and charged with
implementing a national victimization survey.163
In the early 1970s, LEAA, in cooperation with the Census Bureau, worked to
develop a national victimization survey, which would come to be known as the
National Crime Survey (NCS). The pilot studies for the NCS demonstrated that a
large national sample of households would be required to obtain an accurate estimate
of some crimes.164 The Census Bureau was chosen to conduct the NCS because it
was the only organization that had the capacity to field such a large survey.165 During
the development of the NCS, the survey’s methodology was refined based on some

155

Ibid.

156

Ibid.

157

Ibid.

158

Ibid.

159

David Cantor and James P. Lynch, “Self-Report Surveys as Measures of Crime and
Criminal Victimization,” in U.S. Department of Justice, Office of Justice Programs,
National Institute of Justice, Criminal Justice 2000, Volume 4, NCJ 182411, July 2000, p.
105, hereafter “D. Cantor and J.P. Lynch, ‘Self-Report Surveys as Measures of Crime and
Criminal Victimization.’”

160

C.M. Rennison and M. Rand, “Introduction to the NCVS,” p. 20.

161

Ibid.

162

The LEAA was the predecessor to the Office of Justice Programs.

163

C.M. Rennison and M. Rand, “Introduction to the NCVS,” p. 20.

164

D. Cantor and J.P. Lynch, “Self-Report Surveys as Measures of Crime and Criminal
Victimization,” p. 105.

165

Ibid.

CRS-24
of the lessons learned from the three pilot studies.166 There were a series of pretests,
trial surveys, and record-check experiments167 to help address some of the
methodological issues associated with implementing a nationwide victimization
survey.168 Some of the issues examined included
!

the use of a single household respondent, as opposed to interviewing
everyone in the household;

!

the respondent’s ability to recall events;

!

the length of the reference period;

!

the minimum age of the respondent; and

!

the appropriate question cues and wording.169

As a result of the studies, the NCS chose to interview all members of the
household about victimizations they experienced.170 It was decided that the NCS
would use a six-month reference period.171 It was also decided that only one person
(referred to as a “household respondent”) would answer questions about crimes
against household property.172
The first NCS was conducted in July 1972 by the Census Bureau.173 The NCS
was originally composed of four interrelated surveys: a national sample of
households, referred to as the “Crime Panel”; a sample of households from central
cities;174 and a national and central city sample of commercial establishments.175 As

166

Ibid.

167

Record-check experiments involve comparing police records to reported victimizations
to determine whether crimes are being reported and, if so, how frequently they are being
reported.
168

Ibid.

169

C.M. Rennison and M. Rand, “Introduction to the NCVS,” pp. 20-21.

170

D. Cantor and J.P. Lynch, “Self-Report Surveys as Measures of Crime and Criminal
Victimization,” p. 106.

171

Ibid.

172

Ibid.

173

U.S. Department of Commerce, Bureau of the Census, National Crime Victimization
Survey: Interviewing Manual for Field Representatives, February 2003, p. A1-5, hereafter
“Census Bureau, NCVS Interviewing Manual.”
174

Data collected from a nationwide sample of households in central cities were designed
to estimate the level and change of victimization for a selected set of crime committed
against residents of major cities in the United States. The surveys were designed to obtain
benchmark estimates of crime in cities, which could then be updated in subsequent
enumerations for each city. For example, in 1972 and 1975, approximately 12,000
households in eight different cities (Atlanta, Baltimore, Cleveland, Dallas, Denver, Newark
(continued...)

CRS-25
of 1976, data were no longer collected for the sample of households from central
cities, nor were data collected for the national and central city sample of commercial
establishments. Since 1976, the NCS consisted only of the national sample of
households (i.e., the Crime Panel).
In the mid-1970s, in response to concerns about the quality and usefulness of
NCS data, the LEAA asked the National Academy of Sciences (NAS) to evaluate the
NCS.176 In 1976, the NAS published a report that provided recommendations for
how to improve the NCS.177 The NAS found that although the NCS was an effective
instrument for measuring crime, certain aspects of the survey’s methodology and
scope could be improved.178 The NAS recommended that researchers investigate the
following:
!

Enhanced screening questions that would better stimulate
respondents’ recall of victimizations, thus reducing underreporting
resulting from forgotten incidents.

!

Screening questions that would sharpen the concepts of criminal
victimization and diminish the effects of subjective interpretations
of the survey questions.

!

Additional questions on the nature and consequences of
victimizations that would yield useful data for analysis.

!

Enhanced questions and inquiries about domestic violence, rape, and
sexual attack to get better estimates of these victimizations.179

The Bureau of Justice Statistics (BJS) sponsored a research consortium that
investigated the issues raised in the NAS review and provided recommendations that

174

(...continued)
[NJ], Portland [OR], and St. Louis) were surveyed. The central city household survey was
also fielded in the five largest cities in 1973 and 1975. An additional 13 cities received the
survey once in 1974. C.M. Rennison and M. Rand, “Introduction to the NCVS,” p. 21.

175

The national survey of commercial establishments was conducted once in 1972. The
survey of commercial establishments was conducted concurrently with the central city
household survey. Both surveys collected data on robbery and burglary victimizations of
commercial establishments. Ibid.
176

D. Cantor and J.P. Lynch, “Self-Report Surveys as Measures of Crime and Criminal
Victimization,” p. 108.

177

C.M. Rennison and M. Rand, “Introduction to the NCVS,” p. 33.

178

Charles Kindermann, James Lynch, and David Cantor, Effects of the Redesign on
Victimization Estimates, NCJ 164381, April 1997, U.S. Department of Justice, Office of
Justice Programs, Bureau of Justice Statistics, p. 1, hereafter, “C. Kindermann et al., Effects
of the Redesign on Victimization Estimates.”
179

U.S. Department of Justice, Office of Justice Programs, Bureau of Justice Statistics,
National Crime Victimization Survey: Questions and Answers about the Redesign, NCJ
151171, October 1994, p. 4, hereafter “BJS, Questions and Answers about the Redesign.”

CRS-26
would improve the accuracy and utility of the NCS.180 In 1986, the consortium
proposed new instrumentation and procedures to improve the NCS.181
BJS chose to implement the consortium’s proposals and redesign the NCS. BJS
stated that the overall objectives for redesigning the NCS were to increase reporting
of crime victimization and provide additional details on individual crime incidents.182
BJS also had more specific objectives for the redesign, including
!

developing improved screening questions, thereby stimulating recall
of incidents;

!

sharpening concepts of victimization for survey respondents by
providing a more thorough description of criminal incidents, thus
diminishing effects of cognitive and subcultural differences among
respondents;

!

improving data collection techniques by adopting ComputerAssisted Telephone Interviewing (CATI) for some segments of
survey participants;

!

improving measures of rape and sexual attack by asking respondents
directly about these crimes; and

!

providing better measures of domestic violence.183

The recommended changes were phased in as part of a two stage process: nearterm and long-term.184 The near-term changes focused on the NCS’s procedures and
questionnaires, but they were not substantial enough to affect the comparability of
the crime rates for previous years (i.e., they were non-rate affecting changes).185 The
near-term changes were implemented by the Census Bureau in July 1986.186 Longterm changes had a substantial impact on the crime rate reported by the NCS.187 The
long-term changes to the NCS’s design were phased in gradually. Starting in 1989,
BJS and the Census Bureau pre-tested the long-term changes using 5% and 10%

180

Ibid.

181

David Cantor and James P. Lynch, “Exploring the Effects of Changes in Design on the
Analytical Uses of the NCVS Data,” Journal of Quantitative Criminology, vol. 21, no. 3
(2005), p. 295.

182

BJS, Questions and Answers about the Redesign, p. 4.

183

Ibid.

184

Census Bureau, NCVS Interviewing Manual, p. A1-6.

185

Ibid.

186

Ibid.

187

Ibid.

CRS-27
subsamples of the NCS sample.188 After extensive pre-testing, the long-term changes
were fully implemented by BJS in 1992.189 Between 1986 and 1992, the following
changes were made to the survey:
!

Better “short cue” screening questions were added to stimulate
respondent recall of victimization incidents.

!

More thorough descriptions of crime incidents were added in an
effort to help all respondents interpret NCS concepts correctly.

!

CATI was introduced to improve data collection.

!

Specific questions about rape and sexual assaults were added to
improve measurement of these crimes.

!

Screening questions were reworded and added to get a better
measure of domestic violence.190

After the implementation of the redesigned NCS, BJS changed the name of the
NCS to the National Crime Victimization Survey (NCVS). From January 1992
through June 1993, the full NCS-NCVS sample was divided into two parts.191 One
half of the sample was administered the NCS, and the other half was administered
the NCVS.192 BJS chose to give each half of the sample either the NCS or the NCVS
to permit the continuous publication of estimates of the year-to-year change in crime
rates with comparable data while the NCVS was being introduced.193 The procedure
was also intended to provide data on how the reported rate of victimization might
have changed from the NCS to the NCVS.194
Periodically, BJS has expanded the scope of the NCVS to address new issues
in crime. In 1998, Congress required BJS to add questions to the NCVS to identify
188

C.M. Rennison and M. Rand, “Introduction to the NCVS,” p. 37.

189

Ibid.

190

Census Bureau, NCVS Interviewing Manual, pp. A1-6 to A1-7.

191

C. Kindermann et al., Effects of the Redesign on Victimization Estimates, p. 2.

192

Ibid.

193

Ibid.

194

BJS reported that the NCVS accomplished its overall objective of producing higher
estimates of crime rates than the NCS. In general, the implementation of the NCVS had the
effect of increasing the number of crimes counted by the survey. BJS found that the NCVS
produced higher estimates of violent crime rates regardless of the context (i.e., victimized
by a stranger vs. a non-stranger, crime was completed vs. attempted, victimization was
reported to the police vs. not reported). However, the NCVS had a larger impact on the
estimates of non-stranger and attempted crimes and crimes reported to the police than on
stranger, completed and non-reported crime. For household crimes, the NCVS produced
higher estimates of rates for completed crimes and for crimes either reported or unreported
to the police. However, the magnitude of the effect on household crimes is less than the
magnitude of the effect on violent crimes. Ibid., pp.2-3.

CRS-28
crime victims with developmental disabilities.195 In 1999, BJS added questions to the
NCVS to determine the extent to which respondents who were victims of crime
perceived the crimes to be hate crimes.196 In 2001, BJS added questions to the NCVS
to explore the extent to which people were victimized by computer-related crimes.197
In 2004, the computer crimes questions were replaced by questions about identity
theft.198

How NCVS Data Are Collected
NCVS Data. The Census Bureau conducts the NCVS for BJS.199 As shown
in Appendix I, in 2005, data were collected from 67,000 people in 38,600
households. The survey asks respondents whether they have been the victim of
!
!
!
!
!
!
!

rape and sexual assault,
robbery,
simple and aggravated assault,
purse snatching/pickpocketing,
burglary,
theft, or
motor vehicle theft.200

In addition to estimating the number of annual victimizations, the NCVS also
gathers data on the details of each victimization incident. To do this, the survey
collects data on
!

the month, time, and location of the crime;

!

the relationship between the victim and the offender;

!

characteristics of the offender;

!

self-protective actions taken by the victim during the incident and
results of those actions;

!

consequences of the victimization, including any injury or property
loss;

!

whether the crime was reported to the police and the reason for
reporting or not reporting; and

195

See the Crime Victims with Disabilities Awareness Act (P.L. 105-301). C.M. Rennison
and M. Rand, “Introduction to the NCVS,” p. 46.

196

Ibid.

197

Ibid.

198

Ibid.

199

BJS, Questions and Answers about the Redesign, p. 2.

200

Ibid.

CRS-29
!

offender use of weapons, drugs, and alcohol.201

NCVS Methodology. The NCVS sample is selected using a stratified,
multistage cluster sample.202 The sampling process starts by identifying
approximately 2,000 primary sampling units (PSUs) that are composed of standard
metropolitan statistical areas, a county, or a small group of contiguous counties.203
PSUs are stratified with respect to important demographic characteristics, such as
geographic region, population density, population growth rate, and proportion of
nonwhite population.204 A sample of households is chosen from each stratum in a
manner that is proportionate to their representation in the larger population.205 When
a household is selected for the sample, all eligible people in the household are
interviewed. Non-institutionalized persons aged 12 and older living in the United
States are eligible to be interviewed for the NCVS.206 When a household is selected
for the NCVS sample, eligible members of the household are interviewed once every
six months for three years, for a total of seven interviews. After three years, the
household is rotated out of the sample and a new one is brought in. The rotational
panel design of the NCVS is accomplished by dividing all sampled households into
six rotational groups, with each group containing six panels of households.207 Each
month, one panel from each group is interviewed, so that in any given month, onesixth of the sample is being interviewed for the first time, one-sixth is being
interviewed for the second time, and so forth.208
The survey instrument used in the NCVS consists of three parts: the “control
card,” a basic “screen” questionnaire, and crime incident reports. The control card
contains basic administrative information for the sampled household, including the
house’s address and basic household data, such as the household’s income, whether
the house is owned or rented, and the names, age, race, sex, marital status, and
education of all individuals living in the household.209 The control card also contains
a record of visits, telephone calls, interviews, and information about noninterviews.210 Information on the control card is provided by a “knowledgeable
adult” in the household.211 The “knowledgeable adult” is interviewed about

201

Ibid.

202

C.J. Mosher et al., The Mismeasure of Crime, p. 138.

203

Ibid.

204

Ibid.; C.M. Rennison and M. Rand, “Introduction to the NCVS,” p. 24.

205

C.J. Mosher et al., The Mismeasure of Crime, p. 138.

206

Census Bureau, NCVS Interviewing Manual, p. A1-9.

207

C.M. Rennison and M. Rand, “Introduction to the NCVS,” p. 24.

208

Census Bureau, NCVS Interviewing Manual, p. A1-10.

209

C.J. Mosher et al., The Mismeasure of Crime, p. 138.

210

Ibid.

211

Ibid.

CRS-30
victimizations against the household (i.e., burglaries, motor vehicle thefts, and
household larcenies).212
The screen questionnaire is designed to elicit information about whether the
household or a particular respondent has experienced certain types of
victimizations.213 The screen questionnaire provides respondents with a series of
detailed questions and cues about victimizations and situations in which crimes may
take place.214 Questions on the screen questionnaire describe crimes in plain
language, avoiding technical legal terms. To elicit an accurate response, respondents
are provided with detailed features that may characterize a criminal incident.215 If a
screening question elicits a positive response, more information about the incident
is collected on an incident report.
For each separate victimization incident mentioned on the screening
questionnaire, the respondent is asked to complete an incident report. Incident
reports include a series of questions about the particular crime event, the offending
parties, and the consequences of the crime. Some of the questions on incident reports
include the following:
!

Was the crime reported to the police?

!

Was the offense completed or just attempted?

!

Did the victim know the offender, or was the offender identified?

!

If known, what were the demographic characteristics (i.e., race,
gender, age) of the offender?

!

Was a weapon used in the crime?

!

Did the victim resist?

!

Was there any monetary loss or physical injury, or both, that resulted
from the victimization?216

The first interview is conducted in person, and all subsequent interviews, unless
requested by the respondent, are conducted by telephone.217 Data collected during

212

Ibid.

213

Ibid.

214

BJS, Questions and Answers about the Redesign, p. 3.

215

Ibid.

216

C.J. Mosher et al., The Mismeasure of Crime, p. 139.

217

Janet L. Lauritsen, “Social and Scientific Influences on the Measurement of Criminal
Victimization,” Journal of Quantitative Criminology, vol. 21, no. 3 (2005), p. 247, hereafter
“J. Lauritsen, ‘Social and Scientific Influences on the Measurement of Criminal
(continued...)

CRS-31
first interviews are used for bounding purposes and are excluded when calculating
the crime rate.218 In the context of the NCVS, “bounding” refers to a process
whereby the prior interview and the data collected during it are used in subsequent
interviews to ensure that victimizations before the reference period and
victimizations reported in prior interviews are not counted twice.219 Bounding
procedures can help reduce the effects of “telescoping,” which refers to the tendency
of people to incorrectly identify the timing of past events.220 For example, if a
respondent is asked whether he or she has been the victim of a crime in the past six
months, the respondent might report a victimization that actually occurred seven
months ago. The bounding procedure provides respondents with both a cognitive
and mechanical bound.221 The prior interview can serve as an event that respondents
can use to help determine whether a victimization occurred within the current
reference period.222 Furthermore, if the interviewer finds that a reported victimization
is similar to one reported previously, the interviewer can question the respondent
further to ensure that the reported victimization did indeed occur in the current
reference period.223 Data collected during bounding interviews are not used by BJS
to calculate annual victimization rates.
A growing number of interviews for the NCVS are being conducted via
Computer-Assisted Telephone Interviewing (CATI). Currently, about 30% of all
NCVS interviews are conducted by using CATI.224 As discussed above, the first
interview is conducted face-to-face, and subsequent interviews are conducted by
phone. Face-to-face and non-CATI telephone interviews are conducted using Paper
and Pencil Interviewing (PAPI); that is, the respondent’s answers are recorded on
printed instruments.225 The survey has evolved from one in which all interviews were
done face-to-face to one in which most interviews are conducted over the telephone,
with a growing number of phone interviews employing CATI.226 With CATI,
interviews are conducted from a centralized telephone facility where they read
questions from a computer screen and record answers directly into a computer.227
The computer provides the interviewer with the next appropriate question based on
the last answer; it also allows for automated internal consistency checks and reduces

217

(...continued)
Victimization.’”

218

Ibid.

219

C.M. Rennison and M. Rand, “Introduction to the NCVS,” p. 29.

220

Ibid.

221

Ibid.

222

Ibid.

223

Ibid.

224

Ibid., p. 43.

225

Ibid., p. 28.

226

Ibid., p. 48.

227

BJS, Questions and Answers about the Redesign, p. 6.

CRS-32
transcription errors.228 CATI improves data quality because all interviewers are in
a centralized facility, allowing them to be monitored for adherence to standardized
interviewing techniques.229
In some instances, an interviewer is unable to complete an interview with a
household or an individual in the household (i.e., they are “noninterviews”).230 The
NCVS classifies various types of noninterviews. Because the sample is a sample of
households, and not of the people who live in the household, some sampled
households may not be able to be interviewed.231 For example, the household may
be vacant, occupied by persons who have usual residences elsewhere, or temporarily
or permanently converted to a business.232 In these instances, the households are
removed from the sample, either until the next time the household is to be
interviewed (if the situation is temporary) or permanently, if the household will not
be eligible for interviewing in the future.233 Other noninterviews occur when an
interview cannot be completed with the entire eligible household, or when an
interview cannot be completed with an eligible member of a household.234 Such
noninterviews occur for a variety of reasons, including if no one is home during the
three-week interview period, if the household or persons in the household refuse to
be interviewed, and if the household is not reachable, for example, because of
impassable roads.235
The NCVS does not rely on the respondent or the interviewer to classify
reported victimizations. Rather, victimizations are classified based on details of the
reported incident provided by the respondent.236 For example, a woman does not
have to report that she was the victim of a rape for the victimization to be classified
as a rape. If the details provided by the respondent indicate that the respondent was
the victim of a rape, the victimization will be classified as a rape in the NCVS.
Moreover, if the details of the incident do not meet the criteria necessary to define
a victimization as a particular crime, the victimization will not be counted as a
crime.237 For example, if a respondent believes that he/she was assaulted but the

228

Ibid.

229

Ibid.

230

Michael R. Rand, The National Crime Victimization Survey: 32 Years of Measuring
Crime in the United States, paper prepared for the Siena Group on Social Statistics meeting
in Helsinki, Finland, February 2005, p. 9, hereafter “M.R. Rand, The National Crime
Victimization Survey: 32 Years of Measuring Crime in the United States.”
231

Ibid.

232

Ibid.

233

Ibid.

234

Ibid.

235

Ibid.

236

J. Lauritsen, “Social and Scientific Influences on the Measurement of Criminal
Victimization,” p. 247.

237

BJS, Questions and Answers about the Redesign, p. 3.

CRS-33
details do not meet the criteria of a simple assault, the victimization will not be
counted as a simple assault in the NCVS.

Limitations of NCVS Data
Sampling and Non-sampling Error. As described above, the NCVS
estimates national crime rates by interviewing a sample of households across the
country. Because the NCVS is a sample survey, it is subject to both sampling and
non-sampling error, meaning that the estimated victimization rate might not
accurately reflect the true victimization rate. Whenever samples are used to represent
entire populations, there could be a discrepancy between the sample estimate and the
true value of what the sample is trying to estimate. The NCVS accounts for sampling
error by calculating confidence intervals for estimated rates of victimization.238 For
example, in 2000, the estimated violent crime victimization rate was 27.9
victimizations per 100,000 people aged 12 and older.239 The calculated 95%
confidence interval240 for the estimated violent crime victimization rate was 25.85 to
29.95 victimizations per 100,000 people aged 12 and older.241
The NCVS is also subject to non-sampling error. The methodology employed
by the NCVS attempts to reduce the effects of non-sampling error as much as
possible, but an unquantified amount remains.242 Non-sampling error can result from
respondents not being able to recall victimizations that occurred to them during the
reference period. Non-sampling error can also occur when respondents do not report
crimes to the interviewer. Respondents may not report crimes because they know the
perpetrator or because they are victims of certain crimes frequently enough that they
forget that they were victimized or they do not consider the victimizations important
enough to report.243
Sampling Bias. The NCVS relies on interviews with household members to
collect its data, but it is likely that some people sampled will not complete the survey.
As shown in Appendix G, between 1996 and 2005, anywhere from 9% to 16% of
people included in the sample did not complete the survey. If non-responders differ
from responders in the number of victimizations they experienced, the estimated
238

Michael R. Rand and Callie M. Rennison, “True Crime Stories? Accounting for
Differences in Our National Crime Indicators,” Chance, vol. 15, no. 1 (2002), p. 49,
hereafter “M.R. Rand and C.M Rennison ‘Accounting for Differences in Our National
Crime Indicators.’”

239

Ibid.

240

A confidence interval shows the range within which the true value of a calculated statistic
is likely to fall a certain percentage of the time. In this case, the NCVS estimated that 95%
of the time, the true violent crime victimization rate was in the range of 25.85 to 29.95
victimizations per 100,000 people aged 12 or older. There was a 5% chance that it was
either higher or lower than that range.
241

M.R. Rand and C.M Rennison “Accounting for Differences in Our National Crime
Indicators,” p. 49.
242

Ibid.

243

Ibid.

CRS-34
national victimization rate might be lower or higher than the true victimization rate.
Researchers have reported that homeless people, young males, and members of
minority groups are less likely to be included in the NCVS sample and have higher
rates of victimization than their older, female, non-minority counterparts.244
Series Victimizations. When a respondent experiences six or more similar
but separate victimizations, and when the respondent is unable to recall the details
of each incident well enough to describe them to the interviewer, the interviewer
completes one incident report to cover the series of incidents.245 The incident report
is completed using information from the most recent incident. BJS does not include
series victimizations when it calculates annual victimization rates.246 However, BJS
does use series victimization data in special reports where series victimizations are
an important aspect of the subject being analyzed (e.g., domestic violence).247 In
these instances, one series is counted as one incident.
It is likely that not including series victimization estimates in the annual
victimization estimates would result in an underestimation of the true national
victimization rate. But the question remains, how large would this effect be? Each
year, BJS includes data on the number and percentage of total victimizations reported
as series victimizations. As shown in Figure 1, the percentage of personal crimes
reported as series victimizations ranged from 3.5% in 2001 to 4.7% in 2003 and
2004. The percentage of property crimes reported as series victimizations was
consistent from 2001 to 2004 (0.8%) and decreased to 0.5% in 2005.

244

C.J. Mosher et al., The Mismeasure of Crime, p. 159.

245

C.M. Rennison and M. Rand, “Introduction to the NCVS,” pp. 42-43.

246

U.S. Department of Justice, Office of Justice Programs, Bureau of Justice Statistics,
Criminal Victimization in the United States, 2005 Statistical Tables, National Crime
Victimization Survey, NCJ 215244, December 2006, p. 134.
247

See, for example, Callie Marie Rennison, Intimate Partner Violence and Age of Victim,
1993-99, U.S Department of Justice, Office of Justice Programs, Bureau of Justice Statistics,
NCJ 187635, October 2001.

CRS-35
Figure 1. Percentage of Victimizations Reported as Series
Victimizations, 2000-2005
5.0%
4.5%
4.0%

Percent

3.5%
3.0%
2.5%
2.0%
1.5%
1.0%
0.5%
0.0%
2000

2001

2002

2003

2004

2005

Year
Personal Crimes

Property Crimes

Source: U.S. Department of Justice, Office of Justice Programs, Bureau of Justice Statistics, Criminal
Victimization in the United States, 2005 Statistical Tables, National Crime Victimization Survey, NCJ
215244, December 2006.

Changes in Household Residents. As described above, a sample of
households is selected to be interviewed for the NCVS, and it is the household, not
the people in the household, that remains in the sample. Hence, the interviewer
interviews anyone in the household over the age of 12 at each enumeration, even if
the residents of the household have changed from the previous interview. This can
result in some cases where unbounded interviews can be included in the national
victimization estimates. For example, if a new family moves into the household
while the household is in the sample, the interviews with the family will be
unbounded because the bounding interview for the household was conducted during
the first interview with the household.248 If a family member was under the age of
12 at the time of the bounding interview but turns 12 while the household is in the
sample, the interview with the family member that “aged in” to the sample is
unbounded. As described above, unbounded interviews may result in inflated
estimates of victimizations. It has been estimated that between 17% and 19% of
household and person interviews were unbounded in any given year of data.249
Limitations on the Scope of Crimes Covered. The NCVS collects data
only on crimes that have a victim. Data on “victimless” crimes — such as drug

248

C.M. Rennison and M. Rand, “Introduction to the NCVS,” pp. 30-31.

249

As cited in Ibid.

CRS-36
crimes, prostitution, and gambling — cannot be collected by the NCVS. Data on a
host of other crimes — including illegal weapons possession, murder, crimes
perpetrated against business or commercial establishments, consumer fraud,
possession of stolen property, and public order offenses — are also excluded from
the NCVS. As a result, the crimes that the NCVS collects data on make up a small
part of all criminal offenses committed in the United States.250
Survey Design and Implementation. The design of the NCVS survey
instrument and the methods used to administer it can affect estimated victimization
rates. As described above, changes in the wording of questions associated with the
redesign of the NCVS increased reported rates of victimization. The redesign
showed that the wording of screening questions can influence respondents’ ability to
recall victimizations. Researchers have reported that both incident rates and
subgroup variation in reported victimization are affected by the wording of screening
questions.251 It has been reported that short screening questions may cue a
respondent’s recall of only a small subset of incidents that involved the most serious
or frequent crimes, whereas longer screening questions encourage the recounting of
a fuller range of victimizations.252
In addition to wording and type of questions included in the survey, the survey’s
methods can influence the number of reported victimizations. As discussed above,
the NCVS has started to conduct more interviews using CATI. Researchers have
found that using CATI can increase the number of reported victimizations for some
crimes.253 The use of CATI from a centralized telephone facility has been shown to
increase the number of reported crimes.254 It is believed that the combined effect of
centralization (ability to monitor interviewers) and computerization of the survey
help standardize the interviewer-respondent interaction, resulting in higher and more
realistic crime rates.255 NCVS surveys that used CATI resulted in higher crime rates
than surveys that did not; for example, violence, crimes of theft, and household
larceny increased by 15%-20%, and burglary increased by about 10%.256 CATI’s
effect on motor vehicle thefts was negligible. Because CATI provides greater
anonymity for respondents than in-person interviews, respondents may answer
sensitive questions more honestly, thereby producing a greater number of reported
victimizations.257

250

C.J. Mosher et al., The Mismeasure of Crime, p. 156.

251

Ibid., p. 160.

252

Ibid., pp. 160-161.

253

Ibid., p. 160.

254

U.S. Department of Justice, Office of Justice Programs, Bureau of Justice Statistics,
National Crime Victimization Survey (NCVS) Redesign: Technical Background, NCJ
151172, October 1994.
255

Ibid.

256

Ibid.

257

C.J. Mosher et al., The Mismeasure of Crime, p. 160.

CRS-37
The length of the recall period used by the NCVS can affect estimated
victimization rates. The six-month reference period used by the NCVS was not
chosen because it was the optimal reference period, but rather because it provided a
balance between accuracy and economy.258 Longer reference periods make it difficult
for respondents to recall past victimizations accurately.259 Also, the longer the
reference period, the more likely it is that a greater number of victimizations will be
reported, because respondents are at-risk for victimization for a longer period of time.
Shorter reference periods would increase the cost of conducting the NCVS because
respondents would have to be interviewed more frequently.260

The UCR Compared with the NCVS261
The Department of Justice (DOJ) uses both the UCR and the NCVS to measure
the magnitude, nature, and impact of crime in the United States. Both the UCR and
the NCVS are important because, as one pair of researchers states, “crime, unlike the
weather, is a phenomenon that is not directly observable. No one measure is capable
of providing all the information about the extent and characteristics of crime.”262 The
UCR measures offenses known to the police, and the NCVS collects data on crimes
that people have experienced, whether they were reported to the police or not. DOJ
states, “each program produces valuable information about aspects of the Nation’s
crime problem. Because both the UCR and NCVS programs are conducted for
different purposes, use different methods, and focus on somewhat different aspects
of crime, the information they produce together provides a more comprehensive
panorama of the Nation’s crime problem than either could produce alone.”263
The NCVS was designed to complement the UCR, yet the UCR and the NCVS
serve two different purposes. The primary objective of the UCR is to provide a
reliable set of criminal justice statistics for law enforcement administration,
operation, and management.264 The NCVS was created to provide previously
unavailable information about crime (including crime not reported to the police),
victims, and offenders.265

258

C.M. Rennison and M. Rand, “Introduction to the NCVS,” p. 29.

259

Ibid.

260

Ibid.

261

This section compares only the UCR with the NCVS; it does not compare the NIBRS
with the NCVS because the FBI still reports crime statistics in the UCR summary format.

262

M.R. Rand and C.M Rennison, “Accounting for Differences in Our National Crime
Indicators,” p. 48.

263

U.S. DOJ, The Nation’s Two Crime Measures, p. 1.

264

Ibid., p. 2.

265

Ibid.

CRS-38
The UCR and the NCVS collect data on an overlapping, but not identical, set
of offenses against an overlapping, but not identical, population.266 The NCVS does
not collect data on homicide, arson, or commercial crimes, and the UCR does not
collect offense data on sexual assaults or simple assaults. Because the UCR collects
data on offenses known to police, it includes offenses committed against children
under the age of 12, visitors from other countries, and businesses or organizations.267
The NCVS’s methodology precludes the survey from collecting data on crimes
against these populations.
The methodologies used by the UCR and the NCVS differ in some important
aspects. First, the UCR and the NCVS have different definitions for some crimes.268
One example is the definition used by the UCR and the NCVS for rape. The UCR
defines rape as the “carnal knowledge of a female forcibly and against her will” (see
Appendix B). However, under the NCVS, rape and sexual assault can be perpetrated
against both men and women.269 Second, the UCR and the NCVS use different
methods for calculating the crime rates for some crimes. The crime rates for all Part
I offenses are calculated on a per capita basis (i.e., the number of offenses per
100,000 people).270 The NCVS calculates property crime rates (burglary, theft, and
motor vehicle theft) on a per household basis (i.e., the number of crimes per 1,000
households).271 Third, the methodologies used by both programs are subject to
limitations and sources of error that can affect the quality, accuracy, and reliability
of their estimates and hence influence comparisons of the data produced by the two
programs.272 As discussed above, the UCR is a voluntary program, which means that
some agencies might not submit data for the entire year, or at all. Similarly, because
the NCVS interviews a sample of households, its victimization estimates are subject
to both sampling and nonsampling errors.273

Select Issues
As discussed above, there are issues associated with UCR, NIBRS, and NCVS
data. Moreover, there are issues Congress might face when considering the future
of each program, especially the NIBRS and the NCVS. These issues include (1)
barriers to implementing the NIBRS nationwide, (2) potential increases in the crime
rate because of transitioning to the NIBRS, and (3) cuts in the NCVS sample size and

266

M.R. Rand and C.M Rennison, “Accounting for Differences in Our National Crime
Indicators,” p. 48.

267

Ibid.

268

Ibid., p. 49.

269

Ibid.

270

U.S. DOJ, The Nation’s Two Crime Measures, p. 2.

271

Ibid.

272

M.R. Rand and C.M Rennison, “Accounting for Differences in Our National Crime
Indicators,” p. 49.
273

Ibid.

CRS-39
the effects associated with the decrease in sample size. Each of these issues is
discussed in more detail below.
Implementing the NIBRS Nationwide.274
As discussed above,
implementing the NIBRS system nationwide has been a slow process. The SEARCH
group collected data from the 64 largest law enforcement agencies in the United
States to determine what impediments they face in making the transition to the
NIBRS. SEARCH found that some law enforcement agencies’ record management
systems (RMS) were more capable of making the switch from the UCR to the NIBRS
than others. SEARCH reported that some law enforcement agencies have RMSs that
are unable to report NIBRS data, either because the data are in an incompatible
format (i.e., they still follow the hierarchy rule and fail to capture multiple offenses
and victims), or because they do not record data for all of the mandatory data
elements or code the data in a NIBRS-compliant manner. Some law enforcement
agencies reported that they had antiquated systems that are fragmented and in need
of upgrades or replacement. Other law enforcement agencies have automated
incident-based systems that meet the agency’s operational needs but fail to capture
the necessary data in an appropriate format for NIBRS reporting.
Law enforcement agencies identified seven general impediments to NIBRS
implementation in their jurisdictions:

274

!

Funding: SEARCH reported that the general perception was that
implementing the NIBRS is very costly for local law enforcement
agencies. Law enforcement agencies are concerned that they will
incur a series of new costs, including developing or acquiring new
or upgrading existing hardware or software; implementing
automated incident-based reporting at the street level; hiring new
data entry staff to process the additional data collected; establishing
new quality control procedures; and having to increase the volume
and complexity of training. Law enforcement agencies expressed
concern that NIBRS is not a funding priority among local decision
makers and stakeholders.

!

Uncertainty of benefits: Law enforcement agencies reported that no
clear operational value for the use of NIBRS data has been
established. For example, NIBRS data do not include information
on the address where a crime took place, hence NIBRS data cannot
be used for crime mapping. Absent a demonstration of its practical
use, law enforcement agencies felt that NIBRS data were more
useful to researchers than to them.

!

Policy concerns: Law enforcement agencies expressed concern that
reported crime will increase when they implement the NIBRS
because NIBRS does not use the hierarchy rule, meaning that all

SEARCH, Implementing the National Incident-Based Reporting System: A Project Status
Report, NCJ 165581, July 1997, U.S. Department of Justice, Office of Justice Programs,
Bureau of Justice Statistics.

CRS-40
crimes in an incident will be reported (a more detailed discussion of
this issue can be found below).
!

Administrative issues: According to SEARCH, there was some
concern that law enforcement officers would spend more time
completing incident reports, which would decrease the time they
have to respond to calls for service. Law enforcement agencies were
also concerned about the time that would have to be spent on
training officers on how to complete NIBRS incident reports and the
technical support necessary for ongoing operations.

!

Federal and state reporting: SEARCH reported that some law
enforcement agencies were concerned about the “all or nothing”
policy of NIBRS participation, which meant that if law enforcement
agencies could not meet every NIBRS data reporting element, they
could not participate in the program. Law enforcement agencies
were also concerned about meeting the reporting requirements set
forth by state programs, which had in some cases expanded reporting
requirement beyond those required for the national NIBRS program.

!

Data elements: Law enforcement agencies reported that some of the
data elements, such as the victim-offender relationship, multiple
offenses, and multiple victims, did not provide investigative value.
Other data elements were viewed as being largely subjective (i.e.,
bias motivation and victim ethnicity) or irrelevant (i.e., residential
status of an arrestee or the nature of suspected substance abuse).

!

Education: SEARCH found that law enforcement agencies were
concerned that key decision makers and stakeholders did not have
sufficient or accurate information regarding the objectives or nature
of the NIBRS.

It appears that although local law enforcement agencies are receptive to the idea
of reporting NIBRS data, several barriers prevent law enforcement agencies from
making the switch from the UCR to the NIBRS. Congress may want to consider
whether anything could be done to promote a more rapid expansion of the NIBRS
program. Policy options for Congress might include the following:
!

Appropriate grant funds to be awarded to state and local law
enforcement agencies to allow them to update or expand their crime
data reporting systems. In 2001, BJS awarded over $13 million in
grants to states for the purpose of implementing NIBRS-compatible
systems. Grant funds for this purpose have not been available since
2001.

!

Provide funding to agencies such as the National Institute of Justice
to allow them to develop NIBRS software that could be distributed
at no charge to local law enforcement. Congress may also consider
making grant funds available to local law enforcement agencies to
allow them to purchase NIBRS software from a vendor. This could

CRS-41
allow law enforcement agencies to customize the software to meet
their specifications.
!

Provide funding to an organization such as the Justice Research and
Statistics Association to allow them to provide training and
continued support to local law enforcement agencies that implement
NIBRS systems.

Does the NIBRS Increase the Crime Rate?275 Some local officials have
expressed concern that implementing the NIBRS will result in a higher reported
crime rate in their jurisdictions. As described above, the NIBRS does not use the
hierarchy rule, so all crimes in an incident are reported, unlike the UCR, where only
the most serious offense in an incident is reported. Therefore, local officials are
concerned that crime rates may appear to increase even though the actual number of
crimes committed does not change.
BJS conducted a study that compared NIBRS-computed crime rates to UCR
crime rates for agencies in nine NIBRS-certified states276 for 1991-1996. To be
included in the study, an agency must have submitted at least one full year of data
and it must serve a “nonzero” population (i.e., police departments or sheriff’s offices,
but it would most likely not include state or county police). The study included 4,068
cases277 from 1,131 unique law enforcement agencies. Summary UCR data were
derived from NIBRS data by using a computer program that applied the hierarchy
rule to reported incidents in the NIBRS data.
BJS found that, overall, the difference between the crime rates calculated using
NIBRS and UCR data was small. On average, the NIBRS index crime rate278 was 2%
higher than the UCR crime rate. On average, the NIBRS violent crime rate was
higher than the UCR violent crime rate279 by less than 1%, and the NIBRS property
crime rate280 was higher than the UCR property crime rate by slightly more than 2%.
However, the difference between the NIBRS rate and the UCR rate varied depending
on the crime. For murder, the NIBRS and UCR rates were the same. For rape,
robbery, and aggravated assault, the difference between the NIBRS and UCR rates
275

Ramona R. Rantala, Effects of NIBRS on Crime Statistics, NCJ 178890, July 2000, U.S.
Department of Justice, Office of Justice Programs, Bureau of Justice Statistics, p. 2,
hereafter, “R.R. Rantala, Effects of NIBRS on Crime Statistics.”
276

The nine NIBRS-certified states were Idaho, Iowa, Massachusetts, Michigan, North
Dakota, South Carolina, Utah, Vermont, and Virginia. Ibid.
277

A “case” refers to an “agency-year.” For example, 156 agencies submitted one full year
of data, meaning that these 156 agencies represented 156 cases. Another 80 agencies
submitted four full years of data, meaning that these 80 agencies represent 320 cases
(80x4=320). A case includes both NIBRS and summary UCR aggregate crime counts within
each agency for each year an agency reported 12 months of NIBRS data. Ibid.

278

This included murder, rape, robbery, aggravated assault, burglary, motor vehicle theft,
and larceny/theft.

279

This included murder, rape, robbery, and aggravated assault.

280

This included burglary, motor vehicle theft, and larceny/theft.

CRS-42
was, on average, less than 1%. NIBRS larceny/theft rates were, on average, higher
than UCR larceny/theft rates by about 3%, and NIBRS motor vehicle theft rates were
higher than UCR theft rates by about 4.5%.
BJS also individually evaluated each case to see how the NIBRS crime rates
differed from the UCR crime rates. As shown in Table 1, in 97% of the cases, the
difference between the NIBRS crime rate and the UCR crime rate for violent crimes
was 5.5% or less. By comparison, the percentage of cases where there was a 5.5%
or less difference between the NIBRS crime rate and the UCR crime was smaller
(90% overall) for property offenses, which is not surprising given that most property
offenses would not be reported under the UCR if they were committed in concert
with a violent offense.

Table 1. Number and Percentage of Cases in Which NIBRS
Crime Rates Differ from UCR Crime Rates by 5.5% or Less
Type of Offense Number of Cases
All Index Offenses
3,661
Violent Offenses
3,937
Murder
4,068
Rape
3,957
Robbery
3,954
Aggravated Assault
3,970
Property Offenses
3,643
Burglary
3,953
Motor Vehicle Theft
3,234
Larceny/Theft
3,569

Percentage of
All Cases
90%
97%
100%
97%
97%
98%
90%
97%
80%
88%

Source: Ramona R. Rantala, Effects of NIBRS on Crime Statistics, NCJ 178890, July 2000, U.S.
Department of Justice, Office of Justice Programs, Bureau of Justice Statistics, p. 3.

BJS reported that the distribution of rate changes for all index offenses showed
that 92.5% of the cases had a rate difference of -0.5% to 15.5%.281 Almost 48% of
the cases had a rate difference between -0.5% to 0.5% for index crimes, and 39% of
the cases had no difference between the NIBRS rates and the UCR rates. For violent
crime, the distribution of rate changes showed that 98.9% of the cases had a rate
difference between 0% and 15.5%, 84.3% of cases had a rate difference between 0%
and 0.5%, and 82.2% of the cases had no difference. For property crime, 91.7% of
the cases had a rate difference between -0.5% and 15.5%, 48% of the cases had a rate
difference between -0.5% and 0.5%, and 40.1% of the cases had no difference.

281

NIBRS extends the hotel rule to temporary rental storage units, which means that under
NIBRS, burglary rates can appear to decrease because multiple burglaries of temporary
rental storage units would be reported as one burglary rather than multiple burglaries (as
they would be under the UCR). Hence, the NIBRS index and property crime rates can be
lower than the UCR crime rates. Ibid., p. 5.

CRS-43
Overall, the data show that the transition to NIBRS can increase the reported
crime rate. In most instances, the increase in the crime rate will be small, and
property crimes, rather than violent crimes, are more likely to increase. However,
there are instances where the increase in reported crime rates can be more than
15.5%. BJS reports that jurisdictions with little crime tend to show exaggerated
changes in their crime rates when they switch from the UCR to the NIBRS. Hence,
most of the drastic changes in reported crime rates likely came from jurisdictions that
did not report a lot of crime to begin with.
If or when the FBI chooses to publish Crime in the United States using NIBRS
data, it may influence the way Congress uses crimes statistics to develop policy and
allocate funding. As shown above, the change from the UCR to the NIBRS may
make it appear like the crime rate in some states, counties, and cities has increased.
Congress might want to be aware of the impact that the change to NIBRS could have
on the reported crime rate before deciding whether to allocate more funding to
jurisdictions that showed an increased crime rate. Also, the formula for the Edward
Byrne Memorial Justice Assistance Grant (JAG) Program uses UCR violent crime
data to allocate funding to state and local governments.282 One policy option for
Congress would be to change the JAG formula to incorporate NIBRS data. Another
policy option would be to leave the JAG formula as it currently is and require the FBI
to modify each state’s NIBRS data to produce summary UCR data.
Decreases in the NCVS Sample Size. The sample size used in the
NCS/NCVS has decreased since it was first conducted in the early 1970s. In June
1984, the NCS’s sample size was cut from the original sample size of 72,000
households to 59,000 households.283 Additional cuts to the sample size were
instituted in 1992 (a 10% reduction), 1996 (a 12% reduction), and 2002 (a 4%
reduction).284 All decreases in the sample size were done to reduce costs.285
Even with the NCVS’s decreasing sample size, the size of the sample is still
much larger than most other surveys conducted in the United States. However, as
one researcher warned, decreases in the sample size can affect the ability of the
NCVS data to produce reliable annual measures and changes in annual rates of
statistically rare forms of victimization (such as rape).286 As the size of the sample
decreases, the standard error287 associated with the estimate of the victimization
statistic can increase, which could make it harder to detect statistically significant
282

For more information on JAG, see CRS Report RS22416, Edward Byrne Memorial
Justice Assistance Grant Program: Legislative and Funding History, by Nathan James.

283

M.R. Rand, The National Crime Victimization Survey: 32 Years of Measuring Crime in
the United States, p. 12.
284

Ibid.

285

Ibid.

286

J. Lauritsen, “Social and Scientific Influences on the Measurement of Criminal
Victimization,” p. 249.

287

The standard error of a survey estimate is a measure of the variation among the estimates
from all possible samples. Therefore, it is a measure of the precision (reliability) with which
a particular estimate approximates the average result of all possible samples.

CRS-44
changes in the annual victimization rates or differences in the victimization rates of
two different subgroups of people. For example, if a decrease in sample size results
in an increased standard error for the estimation of assault victimizations, researchers
might not be able to determine whether a change in reported assault victimizations
reflects an actual change in nationwide assault victimizations or simply statistical
variation.
Congress may want to consider whether to provide additional funding to BJS
to allow it to expand the sample size of the NCVS. Additional funding could allow
BJS to expand the sample size to what it was in the 1970s, thereby allowing for more
accuracy in estimating national victimization rates.

CRS-45

Appendix A. Status of UCR and NIBRS Reporting,
by State
State UCR Status as
of November 2004

State
Alabama

State NIBRS Status as of August 2007
Number of
Has a
Agencies Percentage
of
Percentage
State
Reporting
Population
of Crime
UCR
Mandatory
NIBRS
NIBRS
Represented Represented
Program Reportinga
Status
Data
Yes
Yes Developingb
1
2%
2%

Alaska

Yes

No

No Plans

Arizona
Arkansas
California
Colorado
Connecticut
Delaware
District of
Columbia
Florida
Georgia
Hawaii
Idaho
Illinois
Indiana
Iowa
Kansas
Kentucky
Louisiana
Maine
Maryland
Massachusetts
Michigan
Minnesota
Mississippi
Missouri
Montana
Nebraska
Nevada
New
Hampshire
New Jersey
New Mexico
New York
North Carolina
North Dakota

Yes
Yes
Yes
Yes
Yes
Yes

No
No
Yes
Yes
Yes
Yes

Certified
Certified
Testing
Certified
Certified
Certified

5
247

3%
78%

1%
66%

236
93
69

85%
67%
100%

81%
40%
100%

Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
No
Yes
Yes
Yes
Yes

No Developingc
Yes
No Plans
Yes
No Plansd
No Developing
No
Certified
Yes Developinge
No
Testing
Yes
Certified
Yes
Certified
No
Certified
No
Certified
Yes
Certified
No Developing
No
Certified
Yes
Certified
Yes Developing
No
No Plans
No
Certified
No
Certified
Yes
Certified
Yes
No Plans

1

N/A

N/A

1

0.01%

0.02%

142
1

100%
4%

100%
6%

248
424
27
28
15

100%
90%
6%
9%
14%

100%
72%
8%
8%
11%

267
785

76%
100%

69%
100%

4
111
105

0.3%
100%
36%

0.08%
100%
21%

Yes
Yes
No
Yes
Yes
Yes

No
Yes
No
Yes
No
No

220

83%

85%

112

96%

94%

Certified
Testing
Testing
Testing
Testing
Certified

CRS-46
State UCR Status as
of November 2004
Has a
State
UCR
Mandatory
State
Program Reportinga
Ohio
No
No
Oklahoma
Yes
Yes
Oregon
Yes
Yes
Pennsylvania
Yes
No
Rhode Island
Yes
No
South Carolina
Yes
Yes
South Dakota
Yes
No
Tennessee
Yes
No
Texas
Yes
No
Utah
Yes
No
Vermont
Yes
Yes
Virginia
Yes
Yes
Washington
Yes
No
West Virginia
Yes
Yes
Wisconsin
Yes
Yes
Wyoming
Yes
Yes

State NIBRS Status as of August 2007
Number of
Agencies Percentage
Reporting
of
Percentage
NIBRS
NIBRS
Population
of Crime
Data
Status
Represented Represented
Certified
514
70%
70%
Testing
Certified
74
29%
27%
Testing
Certified
59
100%
100%
Certified
513
100%
100%
Certified
140
90%
98%
Certified
575
100%
100%
Certified
89
20%
15%
Certified
91
79%
80%
Certified
85
100%
100%
Certified
438
100%
100%
Certified
3
1%
0.04%
Certified
505
100%
100%
Certified
25
17%
30%
No Plans

Source: U.S. Department of Justice, Office of Justice Programs, Bureau of Justice Statistics and the
Justice Research and Statistics Association, IBR Resource Center.
Notes: “Certified” means the state submits NIBRS production data which are officially accepted by
the FBI. “Testing” means the state submits test data from various agencies to the FBI. “Developing”
means the state/agency is in the process of designing and implementing various levels of data
collection. “No Plans” means that the state has indicated that there are no formal plans or current
interest in participating in NIBRS.
a. States that have mandatory UCR reporting for local law enforcement agencies have passed state
laws that require local law enforcement agencies to report UCR data. Law enforcement agencies
in these states are not required by federal law to report UCR data.
b. Alabama does not have a FBI certified NIBRS program, but one agency in the state has been
certified to submit NIBRS data directly to the FBI.
c. The District of Columbia does not have a FBI certified NIBRS program, but the Washington
Metropolitan Area Transit Authority Police have been certified to submit NIBRS data directly
to the FBI.
d. Georgia does not have a FBI certified NIBRS program, but one agency in the state has been
certified to submit NIBRS data directly to the FBI.
e. Illinois does not have a FBI certified NIBRS program, but one agency in the state has been certified
to submit NIBRS data directly to the FBI.

CRS-47

Appendix B. UCR Part I and Part II Offenses288
The FBI collects data on both the number of offenses known to police and the
number of arrests made for all Part I offenses. The FBI collects data on the number
of arrests made for all Part II offenses. The offenses listed under the “Part I
Offenses” heading are ranked according to the UCR’s hierarchy rule.

Part I Offenses
!
!
!
!
!
!
!
!

Criminal Homicide
Forcible Rape
Robbery
Aggravated Assault
Burglary
Larceny-theft (except motor vehicle theft)
Motor Vehicle Theft
Arson

Part II Offenses
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!
!

288

Other Assaults
Forgery and Counterfeiting
Fraud
Embezzlement
Stolen Property: Buying, Receiving, or Possessing
Vandalism
Weapons: Carrying, Possessing, etc.
Prostitution and Commercialized Vice
Sex Offenses
Drug Abuse Violations
Gambling
Offenses Against the Family and Children
Driving Under the Influence
Liquor Laws
Drunkenness
Disorderly Conduct
Vagrancy
All Other Offenses
Suspicion
Curfew and Loitering Laws (Persons under 18)
Runaways (Persons under 18)

Source: U.S. Department of Justice, Federal Bureau of Investigation, Uniform Crime
Reporting Handbook.

CRS-48

Appendix C. UCR Hierarchy of Part I Offenses289
1. Criminal Homicide
a. Murder and Nonnegligent Manslaughter
b. Manslaughter by Negligence
2. Forcible Rape
a. Rape by Force
b. Attempts to Commit Rape by Force
3. Robbery
a. Firearm
b. Knife or Cutting Instrument
c. Other Dangerous Weapon
d. Strong-arm — Hands, Fists, Feet, etc.
4. Aggravated Assault
a. Firearm
b. Knife or Cutting Instrument
c. Other Dangerous Weapon
d. Strong-arm — Hands, Fists, Feet, etc.
5. Burglary
a. Forcible Entry
b. Unlawful Entry — No Force
c. Attempted Forcible Entry
6. Larceny-theft (except Motor Vehicle Theft)
7. Motor Vehicle Theft
a. Autos
b. Trucks and Buses
c. Other Vehicles
8. Arson
a.-g. Structural
h.-i. Mobile
j. Other

289

Source: U.S. Department of Justice, Federal Bureau of Investigation, Uniform Crime
Reporting Handbook.

CRS-49

Appendix D. NIBRS Data Elements290
Administrative Segment
1. ORI number291
2. Incident number
3. Incident date/hour
4. Cleared exceptionally
5. Exceptional clearance date

Offense Segment
[1. ORI number]
[2. Incident number]
6. UCR offense code
7. Offense attempted/completed
8. Offender(s) suspected of using
8A. Bias motivation
9. Location type
10. Number of premises entered
11. Method of entry
12. Type of criminal activity/gang information
13. Type of weapon/force involved

Property Segment
[1. ORI number]
[2. Incident number]
14. Type property loss/etc.
15. Property description
16. Value of property
17. Date recovered
18. Number of stolen motor vehicles
19. Number of recovered motor vehicles
20. Suspected drug type
21. Estimated drug quantity
22. Type drug measurement

Victim Segment
[1. ORI number]
[2. Incident number]
23. Victim (sequence) number

290

Source: U.S. Department of Justice, Federal Bureau of Investigation, National
Incident-Based Reporting System, Volume 1: Data Collection Guidelines.
291

The FBI identifies each law enforcement agency that submits crime data with an
Originating Agency Identifier (ORI) number. Each reporting agency has a unique ORI
number.

CRS-50
24. Victim connected to UCR offense code(s)
25. Type of victim
26. Age (of victim)
27. Sex (of victim)
28. Race (of victim)
29. Ethnicity (of victim)
30. Resident status (of victim)
31. Aggravated assault/homicide circumstances
32. Additional justifiable homicide circumstances
33. Type injury
34. Offender number(s) to be related
35. Relationship(s) of victim to offender(s)

Offender Segment
[1. ORI number]
[2. Incident number]
36. Offender (sequence) number
37. Age (of offender)
38. Sex (of offender)
39. Race (of offender)

Arrestee Segment
[1. ORI number]
[2. Incident number]
40. Arrestee (sequence) number
41. Arrest (transaction) number
42. Arrest date
43. Type of arrest
44. Multiple Arrestee Segments Indicator
45. UCR arrest offense code
46. Arrestee was armed with
47. Age (of arrestee)
48. Sex (of arrestee)
49. Race (of arrestee)
50. Ethnicity (of arrestee)
51. Resident status (of arrestee)
52. Disposition of arrestee under 18

CRS-51

Appendix E. Relationship Between NIBRS
Data Elements

Source: Michael G. Maxfield, “The National Incident-Based Reporting System: Research and Policy
Applications,” Journal of Quantitative Criminology, vol. 15, no. 2 (1999).

CRS-52

Appendix F. NIBRS Group A and Group B
Offenses292
Group A Offenses
1. Arson
2. Assault Offenses
! Aggravated Assault
! Simple Assault
! Intimidation
3. Bribery
4. Burglary/Breaking and Entering
5. Counterfeiting/Forgery
6. Destruction/Damage/Vandalism of Property
7. Drug/Narcotic Offenses
! Drug/Narcotic Violations
! Drug Equipment Violations
8. Embezzlement
9. Extortion/Blackmail
10. Fraud Offenses
! False Pretenses/Swindle/Confidence Game
! Credit Card/Automated Teller Machine Fraud
! Impersonation
! Welfare Fraud
! Wire Fraud
11. Gambling Offenses
! Betting/Wagering
! Operating/Promoting/Assisting Gambling
! Gambling Equipment Violations
! Sports Tampering
12. Homicide Offenses
! Murder and Nonnegligent Manslaughter
! Negligent Manslaughter
! Justifiable Homicide
13. Kidnapping/Abduction
292

Source: U.S. Department of Justice, Federal Bureau of Investigation, National
Incident-Based Reporting System, Volume 1: Data Collection Guidelines.

CRS-53
14. Larceny/Theft Offenses
! Pocket Picking
! Purse-snatching
! Shoplifting
! Theft from Building
! Theft from Coin-operated Machine or Device
! Theft from Motor Vehicle
! Theft of Motor Vehicle Parts or Accessories
! All Other Larceny
15. Motor Vehicle Theft
16. Pornography/Obscene Materials
17. Prostitution Offenses
! Prostitution
! Assisting or Promoting Prostitution
18. Robbery
19. Sex Offenses, Forcible
! Forcible Rape
! Forcible Sodomy
! Sexual Assault with an Object
! Forcible Fondling
20. Sex Offenses, Nonforcible
! Incest
! Statutory Rape
21. Stolen Property Offenses (receiving, etc.)
22. Weapons Laws Violations

Group B Offenses
1. Bad Checks
2. Curfew/Loitering/Vagrancy Violations
3. Disorderly Conduct
4. Driving Under the Influence
5. Drunkenness
6. Family Offenses, Nonviolent
7. Liquor Law Violations
8. Peeping Tom
9. Runaway
10. Trespass of Real Property
11. All Other Offenses

CRS-54

Appendix G. UCR Offense Definitions293
Part I Offenses
Criminal homicide. (a.) Murder and nonnegligent manslaughter: the willful
(nonnegligent) killing of one human being by another. Deaths caused by negligence,
attempts to kill, assaults to kill, suicides, and accidental deaths are excluded.
Justifiable homicides are classified separately and the definition is limited to: (1) the
killing of a felon by a law enforcement officer in the line of duty; or (2) the killing
of a felon, during the commission of a felony, by a private citizen. ( b.) Manslaughter
by negligence: the killing of another person through gross negligence. Deaths of
persons due to their own negligence, accidental deaths not resulting from gross
negligence, and traffic fatalities are not included in the category “Manslaughter by
negligence.”
Forcible rape. The carnal knowledge of a female forcibly and against her
will. Rapes by force and attempts or assaults to rape, regardless of the age of the
victim, are included. Statutory offenses (no force used — victim under age of
consent) are excluded.
Robbery. The taking or attempting to take anything of value from the care,
custody, or control of a person or persons by force or threat of force or violence
and/or by putting the victim in fear.
Aggravated assault. An unlawful attack by one person upon another for the
purpose of inflicting severe or aggravated bodily injury. This type of assault usually
is accompanied by the use of a weapon or by means likely to produce death or great
bodily harm. Simple assaults are excluded.
Burglary (breaking or entering). The unlawful entry of a structure to
commit a felony or a theft. Attempted forcible entry is included.
Larceny-theft (except motor vehicle theft). The unlawful taking,
carrying, leading, or riding away of property from the possession or constructive
possession of another. Examples are thefts of bicycles, motor vehicle parts and
accessories, shoplifting, pocket-picking, or the stealing of any property or article that
is not taken by force and violence or by fraud. Attempted larcenies are included.
Embezzlement, confidence games, forgery, check fraud, etc. are excluded.
Motor vehicle theft. The theft or attempted theft of a motor vehicle. A
motor vehicle is self-propelled and runs on land surface and not on rails. Motorboats,
construction equipment, airplanes, and farming equipment are specifically excluded
from this category.

293

Source: U.S. Department of Justice, Federal Bureau of Investigation, Uniform Crime
Reporting Handbook.

CRS-55
Arson. Any willful or malicious burning or attempt to burn, with or without
intent to defraud, a dwelling house, public building, motor vehicle or aircraft,
personal property of another, etc.

Part II Offenses
Other assaults (simple). Assaults and attempted assaults which are not of
an aggravated nature and do not result in serious injury to the victim. Stalking,
intimidation, coercion, and hazing are included.
Forgery and counterfeiting. The altering, copying, or imitating of
something, without authority or right, with the intent to deceive or defraud by passing
the copy or thing altered or imitated as that which is original or genuine; or the
selling, buying, or possession of an altered, copied, or imitated thing with the intent
to deceive or defraud. Attempts are included.
Fraud. The intentional perversion of the truth for the purpose of inducing
another person or other entity in reliance upon it to part with something of value or
to surrender a legal right. Fraudulent conversion and obtaining of money or property
by false pretenses. Confidence games and bad checks, except forgeries and
counterfeiting, are included.
Embezzlement. The unlawful misappropriation or misapplication by an
offender to his/her own use or purpose of money, property, or some other thing of
value entrusted to his/her care, custody, or control.
Stolen property: buying, receiving, possessing. Buying, receiving,
possessing, selling, concealing, or transporting any property with the knowledge that
it has been unlawfully taken, as by burglary, embezzlement, fraud, larceny, robbery,
etc. Attempts are included.
Vandalism. To willfully or maliciously destroy, injure, disfigure, or deface
any public or private property, real or personal, without the consent of the owner or
person having custody or control by cutting, tearing, breaking, marking, painting,
drawing, covering with filth, or any other such means as may be specified by local
law. Attempts are included.
Weapons: carrying, possessing, etc. The violation of laws or ordinances
prohibiting the manufacture, sale, purchase, transportation, possession, concealment,
or use of firearms, cutting instruments, explosives, incendiary devices, or other
deadly weapons. Attempts are included.
Prostitution and commercialized vice. The unlawful promotion of or
participation in sexual activities for profit, including attempts. To solicit customers
or transport persons for prostitution purposes; to own, manage, or operate a dwelling
or other establishment for the purpose of providing a place where prostitution is
performed; or to otherwise assist or promote prostitution.
Sex offenses (except forcible rape, prostitution, and
commercialized vice). Offenses against chastity, common decency, morals, and

CRS-56
the like. Incest, indecent exposure, and statutory rape are included. Attempts are
included.
Drug abuse violations. The violation of laws prohibiting the production,
distribution, and/or use of certain controlled substances. The unlawful cultivation,
manufacture, distribution, sale, purchase, use, possession, transportation, or
importation of any controlled drug or narcotic substance. Arrests for violations of
state and local laws, specifically those relating to the unlawful possession, sale, use,
growing, manufacturing, and making of narcotic drugs. The following drug
categories are specified: opium or cocaine and their derivatives (morphine, heroin,
codeine); marijuana; synthetic narcotics — manufactured narcotics that can cause
true addiction (demerol, methadone); and dangerous nonnarcotic drugs (barbiturates,
benzedrine).
Gambling. To unlawfully bet or wager money or something else of value;
assist, promote, or operate a game of chance for money or some other stake; possess
or transmit wagering information; manufacture, sell, purchase, possess, or transport
gambling equipment, devices, or goods; or tamper with the outcome of a sporting
event or contest to gain a gambling advantage.
Offenses against the family and children. Unlawful nonviolent acts by
a family member (or legal guardian) that threaten the physical, mental, or economic
well-being or morals of another family member and that are not classifiable as other
offenses, such as Assault or Sex Offenses. Attempts are included.
Driving under the influence. Driving or operating a motor vehicle or
common carrier while mentally or physically impaired as the result of consuming an
alcoholic beverage or using a drug or narcotic.
Liquor laws. The violation of state or local laws or ordinances prohibiting the
manufacture, sale, purchase, transportation, possession, or use of alcoholic beverages,
not including driving under the influence and drunkenness. Federal violations are
excluded.
Drunkenness. To drink alcoholic beverages to the extent that one’s mental
faculties and physical coordination are substantially impaired. Driving under the
influence is excluded.
Disorderly conduct. Any behavior that tends to disturb the public peace or
decorum, scandalize the community, or shock the public sense of morality.
Vagrancy. The violation of a court order, regulation, ordinance, or law
requiring the withdrawal of persons from the streets or other specified areas;
prohibiting persons from remaining in an area or place in an idle or aimless manner;
or prohibiting persons from going from place to place without visible means of
support.
All other offenses. All violations of state or local laws not specifically
identified as Part I or Part II offenses, except traffic violations.

CRS-57
Suspicion. Arrested for no specific offense and released without formal
charges being placed.
Curfew and loitering laws (persons under age 18). Violations by
juveniles of local curfew or loitering ordinances.
Runaways (persons under age 18). Limited to juveniles taken into
protective custody under the provisions of local statutes.

CRS-58

Appendix H. NIBRS Offense Definitions294
Group A Offenses
Arson. To unlawfully and intentionally damage or attempt to damage any real
or personal property by fire or incendiary device.
Assault Offenses. An unlawful attack by one person upon another.
Aggravated Assault. An unlawful attack by one person upon another
wherein the offender uses a weapon or displays it in a threatening manner, or the
victim suffers obvious severe or aggravated bodily injury involving apparent broken
bones, loss of teeth, possible internal injury, severe laceration, or loss of
consciousness.
Simple Assault. An unlawful physical attack by one person upon another
where neither the offender displays a weapon, nor the victim suffers obvious severe
or aggravated bodily injury involving apparent broken bones, loss of teeth, possible
internal injury, severe laceration, or loss of consciousness.
Intimidation. To unlawfully place another person in reasonable fear of bodily
harm through the use of threatening words and/or other conduct but without
displaying a weapon or subjecting the victim to actual physical attack.
Bribery. The offering, giving, receiving, or soliciting of anything of value (i.e.,
a bribe, gratuity, or kickback) to sway the judgment or action of a person in a position
of trust or influence.
Burglary/Breaking and Entering. The unlawful entry into a building or
other structure with the intent to commit a felony or a theft.
Counterfeiting/Forgery. The altering, copying, or imitation of something,
without authority or right, with the intent to deceive or defraud by passing the copy
or thing altered or imitated as that which is original or genuine or the selling, buying,
or possession of an altered, copied, or imitated thing with the intent to deceive or
defraud.
Destruction/Damage/Vandalism of Property. To willfully or maliciously
destroy, damage, deface, or otherwise injure real or personal property without the
consent of the owner or the person having custody or control of it.
Drug/Narcotic Offenses. The violation of laws prohibiting the production,
distribution, and/or use of certain controlled substances and the equipment or devices
utilized in their preparation and/or use.

294

Source: U.S. Department of Justice, Federal Bureau of Investigation, National
Incident-Based Reporting System, Volume 1: Data Collection Guidelines.

CRS-59
Drug/Narcotic Violations. The unlawful cultivation, manufacture,
distribution, sale, purchase, use, possession, transportation, or importation of any
controlled drug or narcotic substance.
Drug Equipment Violations. The unlawful manufacture, sale, purchase,
possession, or transportation of equipment or devices utilized in preparing and/or
using drugs or narcotics.
Embezzlement. The unlawful misappropriation by an offender to his/her own
use or purpose of money, property, or some other thing of value entrusted to his/her
care, custody, or control.
Extortion/Blackmail. To unlawfully obtain money, property, or any other
thing of value, either tangible or intangible, through the use or threat of force, misuse
of authority, threat of criminal prosecution, threat of destruction of reputation or
social standing, or through other coercive means.
Fraud Offenses. The intentional perversion of the truth for the purpose of
inducing another person or other entity in reliance upon it to part with something of
value or to surrender a legal right.
False Pretenses/Swindle/Confidence Game.
The intentional
misrepresentation of existing fact or condition or the use of some other deceptive
scheme or device to obtain money, goods, or other things of value.
Credit Card/Automated Teller Machine Fraud. The unlawful use of a
credit (or debit) card or automatic teller machine for fraudulent purposes.
Impersonation. Falsely representing one’s identity or position and acting in
the character or position thus unlawfully assumed to deceive others and thereby gain
a profit or advantage, enjoy some right or privilege, or subject another person or
entity to an expense, charge, or liability that would not have otherwise been incurred.
Welfare Fraud. The use of deceitful statements, practices, or devices to
unlawfully obtain welfare benefits.
Wire Fraud. The use of an electric or electronic communications facility to
intentionally transmit a false and/or deceptive message in furtherance of a fraudulent
activity.
Gambling Offenses. To unlawfully bet or wager money or something else
of value; assist, promote, or operate a game of chance for money or some other stake;
possess or transmit wagering information; manufacture, sell, purchase, possess, or
transport gambling equipment, devices, or goods; or tamper with the outcome of a
sporting event or contest to gain a gambling advantage.
Betting/Wagering. To unlawfully stake money or something else of value on
the happening of an uncertain event or on the ascertainment of a fact in dispute.

CRS-60
Operating/Promoting/Assisting Gambling. To unlawfully operate,
promote, or assist in the operation of a game of chance, lottery, or other gambling
activity.
Gambling Equipment Violations. To unlawfully manufacture, sell, buy,
possess, or transport equipment, devices, and/or goods used for gambling purposes.
Sports Tampering. To unlawfully alter, meddle in, or otherwise interfere
with a sporting contest or event for the purpose of gaining a gambling advantage.
Homicide Offenses. The killing of one human being by another.
Murder and Nonnegligent Manslaughter. The willful (nonnegligent)
killing of one human being by another.
Negligent Manslaughter. The killing of another person through negligence.
Justifiable Homicide (Not a crime). The killing of a perpetrator of a
serious criminal offense by a peace officer in the line of duty, or the killing, during
the commission of a serious criminal offense, of the perpetrator by a private
individual.
Kidnapping/Abduction. The unlawful seizure, transportation, and/or
detention of a person against his/her will or of a minor without the consent of his/her
custodial parent(s) or legal guardian.
Larceny/Theft Offenses. The unlawful taking, carrying, leading, or riding
away of property from the possession or constructive possession of another person.
Pocket-picking. The theft of articles from another person’s physical
possession by stealth where the victim usually does not become immediately aware
of the theft.
Purse-snatching. The grabbing or snatching of a purse, handbag, etc., from
the physical possession of another person.
Shoplifting. The theft by someone other than an employee of the victim of
goods or merchandise exposed for sale.
Theft from Building. A theft from within a building which is either open to
the general public or to which the offender has legal access.
Theft from Coin-operated Machine or Device. A theft from a machine
or device that is operated or activated by the use of coins.
Theft from Motor Vehicle (Except Theft of Motor Vehicle Parts or
Accessories). The theft of articles from a motor vehicle, locked or unlocked.

CRS-61
Theft of Motor Vehicle Parts or Accessories. The theft of any part or
accessory affixed to the interior or exterior of a motor vehicle in a manner which
would make the item an attachment of the vehicle or necessary for its operation.
All Other Larceny. All thefts that do not fit any of the definitions of the
specific subcategories of Larceny/Theft listed above.
Motor Vehicle Theft. The theft of a motor vehicle.
Pornography/Obscene Material. The violation of laws or ordinances
prohibiting the manufacture, publishing, sale, purchase, or possession of sexually
explicit material (e.g., literature or photographs).
Prostitution Offenses. To unlawfully engage in or promote sexual activities
for profit.
Prostitution. To unlawfully engage in sexual relations for profit.
Assisting or Promoting Prostitution. To solicit customers or transport
persons for prostitution purposes; to own, manage, or operate a dwelling or other
establishment for the purpose of providing a place where prostitution is performed;
or to otherwise assist or promote prostitution.
Robbery. The taking or attempting to take anything of value under
confrontational circumstances from the control, custody, or care of another person
by force or threat of force or violence and/or by putting the victim in fear of
immediate harm.
Sex Offenses (Forcible). Any sexual act directed against another person,
forcibly and/or against that person’s will or not forcibly or against the person’s will
in instances where the victim is incapable of giving consent.
Forcible Rape. The carnal knowledge of a person, forcibly and/or against that
person’s will or not forcibly or against the person’s will in instances where the victim
is incapable of giving consent because of his/her temporary or permanent mental or
physical incapacity.
Forcible Sodomy. Oral or anal sexual intercourse with another person,
forcibly and/or against that person’s will or not forcibly or against the person’s will
in instances where the victim is incapable of giving consent because of his/her youth
or because of his/her temporary or permanent mental or physical incapacity.
Sexual Assault with an Object. To use an object or instrument to
unlawfully penetrate, however slightly, the genital or anal opening of the body of
another person, forcibly and/or against that person’s will or not forcibly or against the
person’s will in instances where the victim is incapable of giving consent because of
his/her youth or because of his/her temporary or permanent mental or physical
incapacity.

CRS-62
Forcible Fondling. The touching of the private body parts of another person
for the purpose of sexual gratification, forcibly and/or against that person’s will or
not forcibly or against the person’s will in instances where the victim is incapable of
giving consent because of his/her youth or because of his/her temporary or permanent
mental or physical incapacity.
Sex Offenses (Nonforcible). Unlawful, nonforcible sexual intercourse.
Incest. Nonforcible sexual intercourse between persons who are related to
each other within the degrees wherein marriage is prohibited by law.
Statutory Rape. Nonforcible sexual intercourse with a person who is under
the statutory age of consent.
Stolen Property Offenses. Receiving, buying, selling, possessing,
concealing, or transporting any property with the knowledge that it has been
unlawfully taken, as by Burglary, Embezzlement, Fraud, Larceny, Robbery, etc.
Weapons Laws Violations. The violation of laws or ordinances prohibiting
the manufacture, sale, purchase, transportation, possession, concealment, or use of
firearms, cutting instruments, explosives, incendiary devices, or other deadly
weapons.

Group B Offenses
Bad Checks. Knowingly and intentionally writing and/or negotiating checks
drawn against insufficient or nonexistent funds.
Curfew/Loitering/Vagrancy Violations. The violation of a court order,
regulation, ordinance, or law requiring the withdrawal of persons from the streets or
other specified areas; prohibiting persons from remaining in an area or place in an
idle or aimless manner; or prohibiting persons from going from place to place
without visible means of support.
Disorderly Conduct. Any behavior that tends to disturb the public peace or
decorum, scandalize the community, or shock the public sense of morality.
Driving Under the Influence. Driving or operating a motor vehicle or
common carrier while mentally or physically impaired as the result of consuming an
alcoholic beverage or using a drug or narcotic.
Drunkenness. To drink alcoholic beverages to the extent that one’s mental
faculties and physical coordination are substantially impaired.
Family Offenses (Nonviolent). Unlawful, nonviolent acts by a family
member (or legal guardian) that threaten the physical, mental, or economic
well-being or morals of another family member and that are not classifiable as other
offenses, such as Assault, Incest, Statutory Rape, etc.

CRS-63
Liquor Law Violations. The violation of laws or ordinances prohibiting the
manufacture, sale, purchase, transportation, possession, or use of alcoholic beverages.
Peeping Tom. To secretly look through a window, doorway, keyhole, or other
aperture for the purpose of voyeurism.
Runaway. A person under 18 years of age who has left home without the
permission of his/her parent(s) or legal guardian.
Trespass of Real Property. To unlawfully enter land, a dwelling, or other
real property.
All Other Offenses. All crimes that are not Group “A” offenses and not
included in one of the specifically named Group “B” crime categories listed
previously.

CRS-64

Appendix I. Number of Households and Persons
Interviewed for the NCVS, by Year

Year

Number of
Households
Interviewed

Household
Response Rate

Number of
Persons
Interviewed

Response Rate
for Persons

1996

45,000

93%

85,330

91%

1997

43,000

95%

79,470

90%

1998

43,000

94%

78,900

89%

1999

43,000

93%

77,750

89%

2000

43,000

93%

79,710

90%

2001

44,000

93%

79,950

89%

2002

42,000

92%

76,050

87%

2003

42,000

92%

74,520

86%

2004

42,000

91%

74,500

86%

2005

38,600

91%

67,000

84%

Source: U.S. Department of Justice, Office of Justice Programs, Bureau of Justice Statistics, Criminal
Victimization in the United States, 2005 Statistical Tables, National Crime Victimization Survey, NCJ
215244, Dec. 2006.