The U.S. Department of Justice administers two statistical programs to measure the magnitude, nature, and impact of crime in the United States: the Uniform Crime Reporting (UCR) Program and the National Crime Victimization Survey (NCVS). Because 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 overview of the nation’s crime problem than either could provide alone.
The FBI’s UCR Program, which began in 1929, collects information on the following crimes reported to law-enforcement authorities: murder and nonnegligent manslaughter, forcible rape, robbery, aggravated assault, burglary, larceny-theft, motor vehicle theft, and arson.
The UCR Program compiles data from monthly law-enforcement reports or individual crime-incident records transmitted directly to the FBI or to centralized state agencies that then report to the FBI. This Program presents crime counts for the U.S. as a whole, as well as for regions, states, counties, cities, towns, tribal law-enforcement, and colleges and universities.
The Bureau of Justice Statistics’ (BJS) NCVS, which began in 1973, provides a detailed picture of crime incidents, victims, and trends. Two times per year, U.S. Census Bureau personnel interview household members in a nationally representative sample of approximately 43,000 households (about 76,000 people). In all, approximately 150,000 interviews of persons age 12 or older are conducted annually. Households stay in the sample for 3 years, and new households rotate into the sample on an ongoing basis. These surveys collect detailed information on the frequency and nature of the crimes of rape, sexual assault, personal robbery, aggravated and simple assault, household burglary, theft, and motor vehicle theft. They do not measure homicide or commercial crimes (such as burglaries of stores).
The NCVS collects information on crimes suffered by individuals and households, whether or not those crimes were reported to law enforcement. The survey provides information about victims (age, sex, race, ethnicity, marital status, income, and educational level), offenders (sex, race, approximate age, and victim-offender relationship), and the crimes (time and place of occurrence, use of weapons, nature of injury, and economic consequences).
Because the BJS designed the NCVS to complement the UCR Program, the two programs share many similarities. For example, rape, robbery, theft, and motor vehicle theft are defined virtually identically by both the UCR and the NCVS.
There are also significant differences between the two programs. First, the two programs were created to serve different purposes. The UCR Program’s primary objective is to provide a reliable set of criminal-justice statistics for law-enforcement administration, operation, and management. The NCVS is intended to provide information about crime (including crime not reported to police), victims, and offenders.
Second, the two programs measure an overlapping but nonidentical set of crimes. The NCVS includes crimes both reported and not reported to law enforcement. The NCVS excludes, but the UCR includes, homicide, arson, commercial crimes, and crimes against children under age 12.
Third, because of methodology, the NCVS and UCR definitions of some crimes differ. For example, the UCR defines burglary as the unlawful entry or attempted entry of a structure to commit a felony or theft. The NCVS, not wanting to ask victims to ascertain offender motives, defines burglary as the entry or attempted entry of a residence by a person who had no right to be there.
Fourth, for property crimes (burglary, theft, and motor vehicle theft), the two programs calculate crime rates using different bases. The UCR rates for these crimes are per capita (number of crimes per 100,000 persons), whereas the NCVS rates for these crimes are per household (number of crimes per 1,000 households). Because the number of households may not grow, each year, at the same rate as the total population, trend data for rates of property crimes measured by the two programs may not be comparable.
Apparent discrepancies between statistics from the two programs can usually be accounted for by their definitional and procedural differences. For most types of crimes measured by both the UCR and NCVS, analysts familiar with the programs can exclude from analysis those aspects of crime not common to both. Resulting long-term trend lines can be brought into close concordance. The impact of such adjustments is most striking for robbery, burglary, and motor vehicle theft, whose definitions most closely coincide.