DOI: 10.3886/icpsr36858.v1
title: Understanding Arrest Data in the National Incident-based Reporting System (NIBRS), Massachusetts, 2011-2013
title: Version 1

description: These data are part of NACJD's Fast Track Release and are distributed as they were received from the data depositor. The files have been zipped by NACJD for release, but not checked or processed except for the removal of direct identifiers. Users should refer to the accompanying readme file for a brief description of the files available with this collection and consult the investigator(s) if further information is needed. 
 This research examined the reliability of the Federal Bureau of Investigation's National Incident-Based Reporting System (NIBRS) arrests data. Data on crime incidents, including data on whether an arrest was made or a summons issued, are collected from hundreds of law enforcement agencies (LEAs) across the country and then combined by the FBI into a national data set that is frequently used by researchers. This 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. The dataset consists of information collected from the Massachusetts NIBRS database combined with data from LEAs through a survey and includes data on arrests, summons, exceptional clearances, applicable statutes and offense names, arrest dates, and arrestees' sex, race, ethnicity and age for a sample of assault incidents between 2011 and 2013 from the NIBRS.
 The collection contains one SPSS data file (n=480; 32 variables). Qualitative data are not available as part of this collection.
description: 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.
description: 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.
description: 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.
description: Presence of Common Scales: 
					None
description: Response Rates: 
					80.6% of the police agencies represented in the case sample provided data.
description: Datasets: 
					
						DS1: Dataset
description: record abstracts
description: mail questionnaire
description: Arrests in Massachusetts, 2011-2013
				   		Smallest Geographic Unit: None
description: 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.