Understanding Arrest Data in the National Incident-based Reporting System (NIBRS), Massachusetts, 2011-2013 (ICPSR 36858)

Time Period(s) View help for Time Period(s)

Date of Collection View help for Date of Collection

Data Collection Notes View help for Data Collection Notes

Hide

Study Purpose View help for Study Purpose

The purpose of this study was to examine the reliability of arrest data in the National Incident-Based Reporting System. The Federal Bureau of Investigation's National Incident-Based Reporting System (NIBRS) is one of the most important tools for understanding arrests in the United States. Hundreds of law enforcement agencies (LEAs) across the country enter data on crime incidents, including data on whether an arrest was made or a summons issued. These data are compiled by state law enforcement agencies and then combined by the FBI into a national data set that is frequently used by researchers. The present study compared arrest data in a sample of cases from NIBRS data files with arrest and summons data collected on the same cases directly from LEAs.

Study Design View help for Study Design

This project used Massachusetts NIBRS data maintained by the Crime Reporting Unit (CRU) of the Massachusetts State Police. A base dataset was extracted from the Massachusetts NIBRS MS-SQL-Server database into a SPSS flat file to serve as a sampling frame. This sampling frame dataset consisted of all assault incidents between the years of 2011 and 2013 of all NIBRS reports submitted to the Massachusetts State Police. The sample was limited to the crimes of aggravated assault, simple assault, intimidation and sexual assault. Because different size LEAs and different offense types may have differed in the reliability of their NIBRS arrest data, a sample was created with equal numbers of cases from small, medium and large departments and equal numbers from each of the four offense types; 480 cases were sampled, 80 each in each combination of the four offense types by three LEA sizes. For each LEA represented in the sample, the research team created an individualized data collection form that listed all the department's cases in the sample, and included the department's Originating Agency Identification (ORI) and the incident-number and incident date for each case. The data collection form was mailed to each police chief with a letter requesting that the department complete the form and mail, fax or email it back. For each case listed, the LEA was asked to record whether or not there was an arrest or summons and whether there was an exceptional clearance. For arrests and summons, researchers also collected data on the applicable statute and offense name, the date of arrest, and arrestees' sex, race, ethnicity and age. The form also asked what record management system the department used.

Sample View help for Sample

This project used Massachusetts NIBRS data maintained by the Crime Reporting Unit (CRU) of the Massachusetts State Police. A base dataset was extracted from the Massachusetts NIBRS MS-SQL-Server database into a SPSS flat file to serve as a sampling frame. This sampling frame dataset consisted of all assault incidents between the years of 2011 and 2013 of all NIBRS reports submitted to the Massachusetts State Police. The sample was limited to the crimes of aggravated assault, simple assault, intimidation and sexual assault. Because different size LEAs and different offense types may have differed in the reliability of their NIBRS arrest data, a sample was created with equal numbers of cases from small, medium and large departments and equal numbers from each of the four offense types; 480 cases were sampled, 80 each in each combination of the four offense types by three LEA sizes.

Time Method View help for Time Method

Universe View help for Universe

Arrests in Massachusetts, 2011-2013

Unit(s) of Observation View help for Unit(s) of Observation

Data Source View help for Data Source

Data Type(s) View help for Data Type(s)

Mode of Data Collection View help for Mode of Data Collection

Description of Variables View help for Description of Variables

The data file, Understanding-Arrest-Data-in-NIBRS----archive-data-file---12-13-17.sav, includes 32 variables with a case count of 480. Variables include the date of the crime incident from NIBRS, the date of arrest from the law enforcement agency, arrestee demographics from the law enforcement agency, exceptional clearances from the law enforcement agency, exceptional clearances and clearance by arrests from NIBRS, counts of offenses, offenders, victims, and arrests in the incident from NIBRS, and counts of murder, rape, robbery, aggravated assault, burglary, larceny, motor vehicle theft and other assault offences in the incident from NIBRS.

Response Rates View help for Response Rates

80.6% of the police agencies represented in the case sample provided data.

Presence of Common Scales View help for Presence of Common Scales

None

Hide

Original Release Date View help for Original Release Date

2018-05-24

Hide

Weight View help for Weight

The weight variable Adjusted_weight corrects for oversampling of certain categories of LEA size and most serious incident offense in the stratified random sampling method used to construct the study sample.

Hide