Crime Classification Systems

In order to understand and identify crime and criminal behavior, investigators collect and classify certain information. The information collected is called “data.” The collection of data serves three main purposes: to test theories about the causes of crime, to increase knowledge about certain offenses and offenders, and to assist with public policy development. After data are collected, they must be classified to compare offenses and offenders across jurisdictions.

One of the earliest criminal classification systems, developed in the latter part of the eighteenth century, was designed to differentiate criminals from noncriminals by physical appearance. As the study of crime and criminality evolved, other scientific disciplines, such as psychology, biology, and sociology, developed their own approaches to criminal classification. These approaches primarily focused on the behaviors or predisposition of offenders to explain the causes of crime. In defining which behaviors would be subject to public sanction, legislatures developed their own classification of criminal offenses. In the United States, although the definition and classification of criminal offenses may differ from state to state, many jurisdictions have adopted some form of the American Law Institute's Model Penal Code, which defines and distinguishes crimes. Today, the principal sources of aggregate crime data in the United States are the FBI's Uniform Crime Reports and the Bureau of the Census's National Crime Victimization Survey. Refinements to the classification systems contained in these instruments have helped researchers expand their knowledge of offenses and offenders. Also, the United Nations Interregional Crime and Justice Research Institute has conducted the International Crime Victim Survey in fifty-six countries to standardize measurement of crime rates and trends across national borders.