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 103 rd 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 110 th 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. 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. 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. 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. 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. 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 ). 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: 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.