Index Crimes

The Eight Index Crimes

The four violent crimes included in the crime index are murder and nonnegligent manslaughter, forcible rape, robbery, and aggravated assault. All these offenses involve the use of force or the threatened use of force.

The UCR defines murder as the willful killing of one human being by another. Attempts are not included in the count of murders but are instead classified as aggravated assaults. For all other index crimes, attempts are counted as equivalent to completed offenses.

Forcible rape was long defined as “the carnal knowledge of a female against her will.” In 2012, the FBI changed the definition of forcible rape to “the penetration, no matter how slight, of the vagina or anus with any body part or object, or oral penetration by a sex organ of another person, without the consent of the victim” (http://blogs.justice.gov/main/archives/1801). The new definition recognizes that both men and women can commit rape or be victimized by rape, as well as expanding the definition beyond penetration of the vagina by a penis. Unfortunately, it is not possible to apply this definition retroactively, so the data discussed in this entry are based on the old definition.

Robbery involves taking or attempting to take something from a person or persons by force or the threat of force. Aggravated assault involves an unlawful attack with the purpose of inflicting serious bodily injury. This often involves the use of a weapon such as a gun or knife.

The index property offenses all involve attempts to acquire things belonging to someone else, but do not involve force. The index property crimes are burglary, larceny/theft, motor vehicle theft, and arson. Burglary involves unlawful entry of a structure to commit a felony or theft. Larceny/theft is taking the property of another. Motor vehicle theft is theft or attempted theft of a motor vehicle. Arson is the willful or malicious burning of a building, motor vehicle, aircraft, or personal property of another. In computing the index of property crime, arson is usually excluded due to its comparative rarity.

Crime Counts and Crime Rates

Data on index crimes are reported by municipal, county, and state law enforcement agencies. Participation in the UCR program is voluntary, so not all law enforcement agencies submit data and some submit incomplete data. Using a variety of [Page 365]techniques, the FBI attempts to estimate the number of offenses for jurisdictions with missing or incomplete data.

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