Comparison - Ucr and Nibrs

The Uniform Crime Report (UCR) from the FBI is the most widely cited crime report. It is used for comparison with victim surveys and self-reports. It came about in 1930 when the Department of Justice compiled and published national crime statistics. It was the major source for United States crime sets until 1974. Most information in the media is usually based on the UCR, although it is not properly reported.

The UCR involves voluntary participation from local police departments who report the crimes known to and recorded by them. However, not all crimes committed are discovered; not all crimes discovered are reported; and not all reported are recorded. The majority of states employ UCR programs in which local departments are required to report. During the 1980s, 98% of metropolitan statistical areas (MSAs), 94% “other” cities, and 90% of rural areas reported to the UCR. The Census Bureau determined that 97% of the population had been covered by this report.

The Uniform Crime Report contains Part I and Part II crimes. Part I are index crimes, or major felonies reported to the police that have been selected for special analysis because of their seriousness, frequency, and likelihood of being reported. Index crimes include: murder and non-negligent manslaughter, burglary, forcible rape, larceny/theft, robbery, motor vehicle theft, aggravated assault, and arson. Part II are non-index crimes such as simple assault, vandalism, gambling, and drunkenness.

The crime rate is represented as the number of crimes per unit of population. This enables control of the population size and allows for fair comparison. However, the crime index is un-weighted, meaning that each offense is summed and given the same weight as all other offenses. The crime rate is the total number of seven of the original index crimes per 100,000 population.

Number of index crimes

Crime rate = Population x 100,000

Some caution should be taken in reference to UCR data usage. The following are some of the UCR’s weaker points:

These statistics are only a portion of the community’s true crime rate (Census Bureau victim surveys find that there may actually be twice the amount of crime as found in the UCR).

In the mid 1960s and 1970s, the crime rate increase had a lot to do with improved communications, better police departments, and more reliable ways of recording and reporting crime.

More crimes were reported as citizen awareness and public morality changed.

Most federal cases, “victimless” crimes, and white-collar crimes were not included in the UCR (more “crime in the streets”, not “crime in the suites”).

If multiple offenses were committed, only the most serious were counted in the report.

Offenses were un-weighted (murder given the same value as robbery, etc).

The National Incident-Based Reporting System (NIBRS) reflects a rather significant change from the old UCR system. Using this new system, local law enforcement agencies create a unit-record report based on every crime incident and every arrest. The old UCR system was only a summary of reported crime,