The National Incident-Based Reporting System ( NIBRS) is the replacement data collection system developed by the FBI to take the place of the older Uniform Crime Reporting ( UCR) system.

The UCR system has a number of limitations:

  • "Hierarchy" rule collects data only on most serious crime in an incident
  • Data collection on a limited number of offenses
  • No data on victims or offenders (except in homicides)
  • No data on date, time, location or other factors of crime
  • No data on victim-offender relationship

Another limitation of the UCR data collection was that crime data was collected on only seven crimes - the "Index Offenses" of murder, rape, robbery, aggravated assault, burglary, larceny, and motor vehicle theft.

With the implementation of NIBRS, all these limitations are gone. NIBRS collects detailed information on the criminal incident, as well as demographics of victims, offenders, and arrestees.

The unit of count for NIBRS is the criminal incident. For each incident reported in NIBRS, there may be data on up to 999 victims, 99 offenders, 99 arrestees, and 10 offenses.

NIBRS collects data on 46 different offense types. There are a total of 53 data elements in the complete FBI data set.

In addition to the federal standards, Massachusetts has added several data fields to the FBI format:

  • Based on state statute, Massachusetts collects hate crime data differently than the FBI, and uses different codes for the various hate crime categories.
  • Massachusetts has added several fields to collect data on law enforcement officers killed or assaulted in the line of duty.
  • The Massachusetts's data set includes a number of fields to identify the specific location of the offense or arrest (latitude, longitude, specific street address, etc.)

The Crime Reporting Unit has worked cooperatively with the Massachusetts Chiefs of Police Association ( MCOPA) to implement this new system. In October, 1989, the MCOPA voted to accept NIBRS as the new standard for police crime reporting. Crime reporting has always been voluntary in Massachusetts, but currently there are 138 city, town, and campus police agencies reporting their crime data to the Massachusetts State Police Crime Reporting Unit in NIBRS format. These agencies cover a residential population of over 2,200,000 and report approximately 35% of all the crime data in the Commonwealth.