Crime Statistics

Accurate measures of crime are valuable for many reasons; they aid in the formulation of criminal justice policy, in the assessment and operations of criminal justice agencies, in the creation of prevention and intervention programs, and in the development of criminological theory. Two long-established federal data collection programs, the Uniform Crime Reports (UCR) begun in 1929 and the National Crime Victimization Survey (NCVS; formerly the National Crime Survey) begun in 1973, have been, and continue to be, used to measure levels of crime in the United States. Each program is characterized by strengths and weaknesses. A third, emerging data collection program, the National Incident Based Reporting System (NIBRS), when fully operational, will draw upon and merge many of the elements from both the NCVS and the UCR into a single data collection program.

The UCR is a summary reporting program overseen by the Federal Bureau of Investigation (FBI). UCR data are voluntarily submitted by local and state law enforcement agencies directly to the FBI or, in some cases, indirectly through state reporting agencies. Each agency produces frequencies for serious [Page 589]index crimes (murder, rape, robbery, aggravated assault, burglary, larceny/theft, motor vehicle theft, and arson) and less serious crimes occurring within its jurisdiction. Because UCR data ultimately come from individual law enforcement agencies, crimes included are only those known by or reported to the police.

The UCR has several key strengths. First, it provides a general view of crime nationwide and for other aggregates (e.g., city, county). Second, the UCR crime statistics for homicide and motor vehicle theft are generally accurate due to the fact that both of these crimes tend to be reported to the police at high rates. Third, the UCR produces comprehensive frequency and incident statistics for homicides as part of the Supplementary Homicide Reports. Nevertheless, despite these strengths, the UCR has the primary limitation of only counting crimes known by or reported to the police. This constitutes a significant weakness considering that a substantial portion (in excess of 50% in 2001) of all crime goes unreported. This underreporting and the resulting underestimate of crime contributed to the creation of an additional measure of crime.

To complement the UCR, the Bureau of Justice Statistics conducts an annual nationwide survey, the NCVS, to estimate rates of victimization across the country. The primary purpose of the NCVS is to provide detailed incident-level victimization data from a nationally representative sample of households, regardless of whether the victimization was reported to law enforcement authorities. The focus of the NCVS on both reported and unreported crime overcame one of the primary weaknesses of UCR data.

The survey is administered to individuals age 12 and older in approximately 45,000 sample households. Crime labels are attached to incidents based on responses to a series of questions representing definitions of particular crimes. NCVS crime categories largely overlap with UCR Index crimes with one exception. The UCR is the only source of homicide data in the United States. In addition to the type and frequency of particular victimizations, the NCVS also provides comprehensive information about the incident itself, including characteristics related to the perpetrator(s), weapon use, reporting behaviors, protective measures, and other specific event information.

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