Statistics: Reporting Systems and Methods

In order to better understand, explain, and control crime, one needs accurate counts of its occurrence. Crime statistics represent the counts of criminal behavior and criminals. They are typically uniform data on offenses and offenders and are derived from records of official criminal justice agencies, from other agencies of control, and from unofficial sources such as surveys of victimization or criminal involvement. Particularly in the case of official crime statistics, they may be published annually or periodically in a relatively standard format of data presentation and analysis.

Official crime statistics are generated at different levels of government (municipal, state, and federal) by a variety of criminal justice agencies (police, court, and corrections) and at different stages in the criminal justice process (arrest, prosecution, conviction, imprisonment, and parole). Official statistics are also produced on the violation of laws, codes, and standards of a variety of administrative and regulatory agencies of control, primarily at the federal level. Official crime statistics are based on the records of those agencies that are the official registrars of criminal behavior and criminals.

Unofficial crime statistics are produced independently of the records of official agencies of crime control. The sources of these statistics are the records of private security and investigative agencies and the data collected by social scientists through experiments and observations, as well as through surveys of victimization and of self-reported criminal involvement.

Crime statistics emerged in the early nineteenth century as an adjunct to the administration of justice, the primary purpose being the measurement of the amount of crime, particularly "to know if crime had increased or decreased" in order to inform crime control policy and practice (Sellin and Wolfgang, p. 9). Early researchers pointed out the ultimately more important purpose of measuring the distribution of crime by a variety of social, demographic, and geographic characteristics. Both official and unofficial crime statistics have distinctive problems and sources of error, but a major one they share is the underestimation of the actual amount of crime. However, it is probable that the various measures generate similar distributions of crime, meaning that there is convergence rather than discrepancy in their depictions of the characteristics and correlates of crime. It is also likely that multiple indicators of crime best inform research, theory, policy, and practice.

The major types of official and unofficial crime statistics are discussed here in terms of their history and contemporary sources; their role as measures of crime; methodological and utilization issues and problems; and the general issue of discrepancy or convergence among crime statistics regarding the distribution and correlates of crime.