How Crime in the United States Is Measured

Nathan James. Congressional Research Service: Report. January 3, 2008.

Introduction

Congress uses data from the Uniform Crime Reports (UCR), the National Incident-Based Reporting System (NIBRS), 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.

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.

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. The impetus for the legislation was a recent increase in the violent crime rate as reported by the UCR. Moreover, both the House and Senate Appropriations 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. 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. 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 (UCR)

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.

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. 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. 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). The Committee decided that offenses known to police would be the most appropriate measure of the incidence of crime in the United States. 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. 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. 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. 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. 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 Possessions. In 1930, Congress, at the urging of IACP, authorized the Attorney General to collect crime data. The Attorney General designated the FBI as the clearinghouse for crime data collected through the UCR.

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.
  • Beginning in 1958, the FBI began to estimate annual crime rates for the nation as a whole. 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. The national crime index was the total number of reported murder, rape, robbery, aggravated assault, burglary, larceny/theft (over $50), and auto theft offenses.
  • 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.
  • 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.
  • 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).
  • In 1978, Congress mandated the collection of arson data. In 1982, Congress required the FBI to permanently count arson as a Part I offense (a definition of “Part I offense” is below). 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), 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. 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.
  • 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.

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 that 98% of all agencies in the nation participated in the UCR in 2005. 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. 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. 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.
  • 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.

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. 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. 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.

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” 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 submitted to the UCR program by local law enforcement agencies also provide data on the basic characteristics—age, sex, and race—of persons arrested. 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. 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. 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. The FBI collects data on incidents in which law enforcement officers are killed, either feloniously or accidently, or assaulted while performing their duties. 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.

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. Scoring criminal offenses refers to counting the number of offenses after they have been classified. 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. Uniformity in the classification and scoring of criminal offenses across jurisdictions is essential for maintaining the integrity of UCR data. In general, reporting law enforcement agencies classify and score attempted crimes as though they were completed. 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.

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. 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. 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. The final exception to the hierarchy rule involves justifiable homicide. In cases of justifiable homicide, two offenses are scored and reported: one for the felonious offense connected with the offender and one for the justifiable homicide, which is reported as an unfounded 58 murder/nonnegilgent manslaughter.

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. 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. 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. 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). 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. 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 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.

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). For crimes against persons, one offense is counted for each victim in the criminal incident. 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. 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. 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. 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. If multiple people are arrested for the same crime, each person is counted as a separate arrest. 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.

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 the 21st century. 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. 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. The study recommended that law enforcement agencies use an incident-based system to report offenses and arrests. 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). The study also recommended that the national UCR program implement a quality assurance program.

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). The FBI chose the South Carolina Law Enforcement Division (SLED) to conduct a pilot study of the newly developed NIBRS guidelines and design specifications. 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. The pilot study ran from March 1 to September 30, 1987, and it resulted in further refinement of NIBRS’s guidelines and specifications.

The FBI presented the NIBRS to law enforcement at a national UCR conference in March 1988. The conference gave the FBI the opportunity to receive feedback on the NIBRS from the law enforcement community. According to the FBI, conference attendees overwhelmingly supported implementation of the NIBRS nationwide. 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. 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.

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 incident are submitted to the FBI in a separate report. 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 arrestee(s), and any property involved in the offense. 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.

NIBRS data are intended to be a by-product of local incident-based reporting (IBR) systems. 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.

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. For Group B offenses, law enforcement agencies are required to submit only arrest reports, which contain data only from the arrestee data segment. 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. 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. The FBI has developed a state certification policy, which uses the following criteria to evaluate the NIBRS data submitted by a state:

  • 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.
  • 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.

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 NIBRS compliant data. 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.

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. 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. 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. 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. 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.

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 law enforcement agencies can report all of the offenses that occurred in a criminal incident.

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). 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. 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. 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.

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.
  • 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.

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. 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 the NIBRS. Neither the UCR nor the NIBRS collect data on political crimes, pricefixing and illegal environmental pollution. Moreover, the UCR and the NIBRS most likely undercount corporate and occupational crimes.

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. 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. 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. 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. 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. 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 they assign more employees to do dispatching, record keeping, and criminal incident reporting.

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. Also, law enforcement agencies are not required to submit a full year of UCR data to the FBI. 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. 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).

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. 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.

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. 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” equals the number of months of data submitted by the law enforcement agency. 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), the crime rate is estimated by applying the crime rate for all other law enforcement agencies in the agency’s population group to the agency’s population. 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 80,000×10.0/100,000). 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 division or region rate. Agency-level estimates are always aggregated into larger geographic areas, such as MSAs, state, geographic division, region, and the nation.

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 same as for reported months. 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.

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. 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).

NCVS’s History

The NCVS began as a way to supplement UCR data. In 1965, President Lyndon Johnson convened the President’s Commission on Law Enforcement and the Administration of Justice (hereafter referred to as “the Commission”). 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. At the time, the UCR was the only source for official crime data, and the Commission found that several limitations associated with the data prevented it from helping the Commission develop policy recommendations. To help rectify some of the limitations associated with UCR data, the Commission recommended the creation of a national survey of crime victimization.

The first crime victimization survey pilot study was conducted in three Washington, D.C., police precincts in the spring of 1966. 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. 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.

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. The supplementary study also surveyed residents of Chicago and Boston about their household’s criminal victimizations. Like the Washington, D.C., pilot study, the supplementary study found that the number of reported victimizations exceeded the number of reported crimes.

A third victimization survey sponsored by the Commission was conducted by the National Opinion Research Center (NORC). 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 interviewed one person in each of 10,000 households nationwide. Like the two previous pilot studies, NORC’s survey found that more crime was being committed than was being reported to law enforcement. 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. 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.

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.” They also demonstrated that a household survey was a reasonable method for estimating the number of criminal victimizations in the United States. The Commission recommended that a national criminal justice statistics center be established to collect victimization data on an ongoing basis. In 1968, the Law Enforcement Assistance Administration (LEAA) was created and charged with implementing a national victimization survey.

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. 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. During the development of the NCS, the survey’s methodology was refined based on some of the lessons learned from the three pilot studies. There were a series of pretests, trial surveys, and record-check experiments to help address some of the methodological issues associated with implementing a nationwide victimization survey. 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.

As a result of the studies, the NCS chose to interview all members of the household about victimizations they experienced. It was decided that the NCS would use a six-month reference period. It was also decided that only one person (referred to as a “household respondent”) would answer questions about crimes against household property.

The first NCS was conducted in July 1972 by the Census Bureau. 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; and a national and central city sample of commercial establishments. As 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. In 1976, the NAS published a report that provided recommendations for how to improve the NCS. 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. 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.

The Bureau of Justice Statistics (BJS) sponsored a research consortium that investigated the issues raised in the NAS review and provided recommendations that would improve the accuracy and utility of the NCS. In 1986, the consortium proposed new instrumentation and procedures to improve the NCS.

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. 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 Computer Assisted 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.

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). The near-term changes were implemented by the Census Bureau in July 1986. Longterm changes had a substantial impact on the crime rate reported by the NCS. 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% subsamples of the NCS sample. After extensive pre-testing, the long-term changes were fully implemented by BJS in 1992. 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.

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. One half of the sample was administered the NCS, and the other half was administered the NCVS. 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. The procedure was also intended to provide data on how the reported rate of victimization might have changed from the NCS to the NCVS.

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 crime victims with developmental disabilities. 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. In 2001, BJS added questions to the NCVS to explore the extent to which people were victimized by computer-related crimes. In 2004, the computer crimes questions were replaced by questions about identity theft.

How NCVS Data Are Collected

NCVS Data. The Census Bureau conducts the NCVS for BJS. 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.

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
  • offender use of weapons, drugs, and alcohol.

NCVS Methodology. The NCVS sample is selected using a stratified, multistage cluster sample. 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. PSUs are stratified with respect to important demographic characteristics, such as geographic region, population density, population growth rate, and proportion of nonwhite population. A sample of households is chosen from each stratum in a manner that is proportionate to their representation in the larger population. 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. 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. 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.

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. The control card also contains a record of visits, telephone calls, interviews, and information about noninterviews. Information on the control card is provided by a “knowledgeable adult” in the household. The “knowledgeable adult” is interviewed about victimizations against the household (i.e., burglaries, motor vehicle thefts, and household larcenies).

The screen questionnaire is designed to elicit information about whether the household or a particular respondent has experienced certain types of victimizations. The screen questionnaire provides respondents with a series of detailed questions and cues about victimizations and situations in which crimes may take place. 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. 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?

The first interview is conducted in person, and all subsequent interviews, unless requested by the respondent, are conducted by telephone. Data collected during first interviews are used for bounding purposes and are excluded when calculating the crime rate. 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. Bounding procedures can help reduce the effects of “telescoping,” which refers to the tendency of people to incorrectly identify the timing of past events. 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. The prior interview can serve as an event that respondents can use to help determine whether a victimization occurred within the current reference period. 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. 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. 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. 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. 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. 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 transcription errors. CATI improves data quality because all interviewers are in a centralized facility, allowing them to be monitored for adherence to standardized interviewing techniques.

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”). 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. For example, the household may be vacant, occupied by persons who have usual residences elsewhere, or temporarily or permanently converted to a business. 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. 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. 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.

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. 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. For example, if a respondent believes that he/she was assaulted but the 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. For example, in 2000, the estimated violent crime victimization rate was 27.9 victimizations per 100,000 people aged 12 and older. The calculated 95% confidence interval for the estimated violent crime victimization rate was 25.85 to 29.95 victimizations per 100,000 people aged 12 and older.

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. 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.

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 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.

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. The incident report is completed using information from the most recent incident. BJS does not include series victimizations when it calculates annual victimization rates. 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). 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.

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

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. 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.

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 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.

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. 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.

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. The use of CATI from a centralized telephone facility has been shown to increase the number of reported crimes. 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. 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%. 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.

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. Longer reference periods make it difficult for respondents to recall past victimizations accurately. 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.

The UCR Compared with the NCVS

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.” 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.”

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. The NCVS was created to provide previously unavailable information about crime (including crime not reported to the police), victims, and offenders.

The UCR and the NCVS collect data on an overlapping, but not identical, set of offenses against an overlapping, but not identical, population. 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. 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. 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. 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). 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). 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. 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.

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 the effects associated with the decrease in sample size. Each of these issues is discussed in more detail below.

Implementing the NIBRS Nationwide. 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:

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 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 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 states 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 cases 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 rate was 2% higher than the UCR crime rate. On average, the NIBRS violent crime rate was higher than the UCR violent crime rate by less than 1%, and the NIBRS property crime rate 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 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

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%. 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.

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. 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. Additional cuts to the sample size were instituted in 1992 (a 10% reduction), 1996 (a 12% reduction), and 2002 (a 4% reduction). All decreases in the sample size were done to reduce costs.

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). 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 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.

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

State UCR Status as of November 2004 State NIBRS Status as of August 2007
State Has a State UCR Program Mandatory

Reporting3

NIBRS

Status

Number of Agencies Reporting NIBRS Data Percentage

of

Population

Represented

Percentage of Crime Represented
Alabama Yes Yes Developing15 1 2% 2%
Alaska Yes No No Plans
Arizona Yes No Certified 5 3% 1%
Arkansas Yes No Certified 247 78% 66%
California Yes Yes Testing
Colorado Yes Yes Certified 236 85% 81%
Connecticut Yes Yes Certified 93 67% 40%
Delaware Yes Yes Certified 69 100% 100%
District of Columbia Yes No Developingc 1 N/A N/A
Florida Yes Yes No Plans
Georgia Yes Yes No Plansd 1 0.01% 0.02%
Hawaii Yes No Developing
Idaho Yes No Certified 142 100% 100%
Illinois Yes Yes Developing*5 1 4% 6%
Indiana No No Testing
Iowa Yes Yes Certified 248 100% 100%
Kansas Yes Yes Certified 424 90% 72%
Kentucky Yes No Certified 27 6% 8%
Louisiana Yes No Certified 28 9% 8%
Maine Yes Yes Certified 15 14% 11%
Maryland Yes No Developing
Massachusetts Yes No Certified 267 76% 69%
Michigan Yes Yes Certified 785 100% 100%
Minnesota Yes Yes Developing
Mississippi No No No Plans
Missouri Yes No Certified 4 0.3% 0.08%
Montana Yes No Certified 111 100% 100%
Nebraska Yes Yes Certified 105 36% 21%
Nevada Yes Yes No Plans
New

Hampshire

Yes No Certified 220 83% 85%
New Jersey Yes Yes Testing
New Mexico No No Testing
New York Yes Yes Testing
North Carolina Yes No Testing
North Dakota Yes No Certified 112 96% 94%

 

State UCR Status as of November 2004 State NIBRS Status as of August 2007
State Has a State UCR Program Mandatory

Reporting3

NIBRS

Status

Number of Agencies Reporting NIBRS Data Percentage

of

Population

Represented

Percentage of Crime Represented
Ohio No No Certified 514 70% 70%
Oklahoma Yes Yes Testing
Oregon Yes Yes Certified 74 29% 27%
Pennsylvania Yes No T esting
Rhode Island Yes No Certified 59 100% 100%
South Carolina Yes Yes Certified 513 100% 100%
South Dakota Yes No Certified 140 90% 98%
Tennessee Yes No Certified 575 100% 100%
Texas Yes No Certified 89 20% 15%
Utah Yes No Certified 91 79% 80%
Vermont Yes Yes Certified 85 100% 100%
Virginia Yes Yes Certified 438 100% 100%
Washington Yes No Certified 3 1% 0.04%
West Virginia Yes Yes Certified 505 100% 100%
Wisconsin Yes Yes Certified 25 17% 30%
Wyoming Yes Yes 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.

  • 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.
  • 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.
  • 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.
  • 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.
  • 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

Appendix B. UCR Part I and Part II Offenses

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

  • 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)

Appendix C. UCR Hierarchy of Part I Offenses

Criminal Homicide
a. Murder and Nonnegligent Manslaughter
b. Manslaughter by Negligence

Forcible Rape
a. Rape by Force
b. Attempts to Commit Rape by Force

Robbery
a. Firearm
b. Knife or Cutting Instrument
c. Other Dangerous Weapon
d. Strong-arm — Hands, Fists, Feet, etc.

Aggravated Assault
a. Firearm
b. Knife or Cutting Instrument
c. Other Dangerous Weapon
d. Strong-arm — Hands, Fists, Feet, etc.

Burglary
a. Forcible Entry
b. Unlawful Entry — No Force
c. Attempted Forcible Entry

Larceny-theft (except Motor Vehicle Theft)

Motor Vehicle Theft
a. Autos
b. Trucks and Buses
c. Other Vehicles

Arson
a.-g. Structural
h.-i. Mobile
j. Other

Appendix D. NIBRS Data Elements

Administrative Segment

1. ORI number
2. Incident number
3. Incident date/hour
4. Cleared exceptionally
5. Exceptional clearance date

Offense Segment

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

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

23. Victim (sequence) number
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

36. Offender (sequence) number
37. Age (of offender)
38. Sex (of offender)
39. Race (of offender)

Arrestee Segment

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

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).

Appendix F. NIBRS Group A and Group B Offenses

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
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

Appendix G. UCR Offense Definitions

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.

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 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.

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.

Appendix H. NIBRS Offense Definitions

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.

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.

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.

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.

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.

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.

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

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.