Conversion of NIBRS Data to Summary Data

Uniform Crime Reports, September 1999

Introduction
Conversion of NIBRS Data to Summary Data

Law enforcement agencies across the Nation began implementing incident-based reporting systems over a decade ago. Today, many agencies are either certified to report crime data through the National Incident-Based Reporting System (NIBRS) or are in the process of developing NIBRS reporting systems. However, until the FBI’s Uniform Crime Reporting (UCR) Program receives the preponderance of data via NIBRS, the FBI will continue to report crime statistics to the Nation in the traditional format. During this period of transition, statistics submitted by agencies that have achieved NIBRS capability are converted to the traditional Summary format and then incorporated into the national crime database. This document explains in detail the procedures followed by the FBI when converting NIBRS data to Summary data.

The conversion procedures illustrated in this document use the 53 NIBRS data elements and their data values to transform NIBRS data to the traditional Summary forms. This information should prove helpful to agencies collecting NIBRS data who want to replicate the FBI’s procedures in order to produce the same data as the Summary portion of the UCR system for offenses, arrests, property types and values, clearances, and homicide details.

The FBI converts NIBRS data by month and agency into the existing Summary format for each UCR form except the Law Enforcement Officers Killed and Assaulted (LEOKA) form, which is not available in NIBRS. Printouts containing Summary data are available to state and local agencies for review each time their NIBRS submissions are received. These Summary printouts, when generated from the NIBRS submissions, contain incident reports that are aggregated by offenses, arrests, property types and values, clearances, and details of homicides.

When converting NIBRS data to Summary data, only one offense is taken from each NIBRS incident. The offense to be reported is selected based on the Hierarchy Rule, which ranks Index offenses from high to low as follows:

NIBRS offense code:
09A - Murder and Nonnegligent Manslaughter
11A - Forcible Rape
120 - Robbery
13A - Aggravated Assault
220 - Burglary/Breaking and Entering
23A-23H - Larceny-theft
240 - Motor Vehicle Theft1

An exception to the rule is arson (offense code 200) if listed. In those situations where an arson occurs in conjunction with one or more additional offenses, the arson is reported and the Hierarchy Rule is applied to the remaining Index crimes. ..more.. by FBI