Improving the Production and Use of Forensic Science, 5 U.S. counties, 2006-2009 (ICPSR 36727)
Version Date: Mar 16, 2022 View help for published
Principal Investigator(s): View help for Principal Investigator(s)
James Anderson, RAND Corporation
https://doi.org/10.3886/ICPSR36727.v1
Version V1
Summary View help for Summary
This study collection sought to thoroughly understand the creation, testing, and use of forensic science in five jurisdictions across the country. A random sample was selected of recent criminal cases in the following jurisdictions and tracked from investigation to adjudication to understand how forensic evidence functions:
- Sacramento County, CA: 990 cases
- Segwick County, KS: 936 cases
- Allegheny County, PA: 978 cases
- Bexar County (San Antonio), TX: 936 cases
- King County, WA: 892 cases
The Principal Investigator sought answers to the following seven primary research questions:
- How often is forensic evidence collected and analyzed and how is it used pre-arrest?
- What are the outcomes of forensic evidence testing?
- What is the effect of forensic evidence on arrest and charging?
- How does forensic evidence affect the plea-bargaining process?
- What effect does forensic evidence have on conviction and sentencing outcomes?
- Does the turnaround time for analysis of forensic evidence have any impact on case disposition?
- Does the institutional configuration of the crime laboratory have any effect on its productivity?
Data for the following types of forensic testing are included in this data collection: hair, fibers, glass, paint, gas chromatography / mass spectrometry (GC/MS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy / energy dispersive x-ray spectroscopy (SEM/EDX), physical match, drug identification, toxicology, serology, combined DNA index system (CODIS), DNA short tandem repeat (Y-STR), blood pattern, test fire, and comparison scope.
Citation View help for Citation
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Funding View help for Funding
Subject Terms View help for Subject Terms
Geographic Coverage View help for Geographic Coverage
Smallest Geographic Unit View help for Smallest Geographic Unit
County
Restrictions View help for Restrictions
This data collection may not be used for any purpose other than statistical reporting and analysis. Use of these data to learn the identity of any person or establishment is prohibited. To protect respondent privacy the data files in this collection are restricted from general dissemination. To obtain these restricted files, researchers must agree to the terms and conditions of a Restricted Data Use Agreement.
Distributor(s) View help for Distributor(s)
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
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The Principal Investigator planned for each of the five surveyed counties to account for approximately 20% of the 4,732 total cases. Also part of the plan was for the five primary crime types of interest (aggravated assault, burglary, murder, rape, and robbery) to account for 20% of the cases in the data file. The desired result was to have roughly 200 cases per county per crime type.
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The Principal Investigator has noted an important limitation within the data Each jurisdiction sampled followed their own procedures for collecting and capturing forensic evidence. Therefore, some of the data, or types of forensic testing, were not available from each county. The following is a list of which study jurisdictions DID NOT have data available for a particular topic.
- Forensic evidence collected: Allegheny
- Witness reports: King, Sacramento, Sedgwick
- Fingerprint comparison: Allegheny, Bexar, Sedgwick
- Toxicology analysis: Bexar, King
- Combined DNA index system (CODIS) entry/result: Allegheny
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In addition to the raw data file approved restricted-data access users will receive a Stata syntax file (.do) provided by the Principal Investigator. This file documents the rationale and procedures for recoding variables performed during analysis.
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This specific data collection was one of four overlapping studies conducted by the Principal Investigator regarding forensic evidence in the criminal justice system. The other three areas of data collected, but not associated with this specific data collection, included:
- qualitative interviews with law enforcement, forensic scientists, and district attorneys to understand how forensic evidence is created and used;
- analyzed data collected in the Bureau of Justice Statistics censuses of crime labs in the United States in order to determine what effects, if any, payment system and organizational structure had on laboratory productivity and public safety impact;
- and conducted a study of a sample of prosecutors and defense counsel with experimental manipulations to understand how forensic evidence affected the perceived strength of the case during plea bargaining.
Study Purpose View help for Study Purpose
The project's primary goal is to better understand the effect of forensic science on the resolution and outcome of criminal cases. There was particular interest in understanding how forensic analysis affects the probability that a case progresses from one stage to the next in the criminal justice system.
The Principal Investigator sought answers to the following seven primary research questions:
- How often is forensic evidence collected and analyzed and how is it used pre-arrest?
- What are the outcomes of forensic evidence testing?
- What is the effect of forensic evidence on arrest and charging?
- How does forensic evidence affect the plea-bargaining process?
- What effect does forensic evidence have on conviction and sentencing outcomes?
- Does the turnaround time for analysis of forensic evidence have any impact on case disposition?
- Does the institutional configuration of the crime laboratory have any effect on its productivity?
Study Design View help for Study Design
The five study sites were selected based on the following criteria:
- diverse institutional configurations of crime labs in the criminal justice system;
- two of the sites participating in the National Incident-Based Reporting System (NIBRS);
- broad range of law enforcement agencies in terms of size and geographic diversity;
- jurisdictions have adopted a variety of policies to prioritize forensic testing.
Sample View help for Sample
For each site, the Principal Investigator sought to collect a random sample of 200 cases for each of four crimes: aggravated assault, burglary, rape, and robbery. These cases were generated from each law enforcement agency's comprehensive listing of reported crimes that occurred between 2007 and 2009. Because homicide is a less common event every recorded murder over the three-year period was requested for all study sites. In all five jurisdictions the calendar year 2006 was added to increase the homicide sample size and the number of fully adjudicated cases.
Time Method View help for Time Method
Universe View help for Universe
Reported criminal cases of aggravated assault, burglary, murder, rape, and robbery within the counties of Allegheny (PA), Bexar (TX), King (WA), Sacramento (CA), and Sedgwick (KS) between the years 2006-2009.
Unit(s) of Observation View help for Unit(s) of Observation
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
Information on over a dozen forensic tests are provided in the data file. For example the test type variables HAIRS, FIBERS, GLASS, PAINT, DRUG_ID, and TOX_ID denote if the evidence type was analyzed. For almost all forensic test types, the following three variables were also collected.
- TestType_RES: Result of evidence analysis.
- TestType_REQUEST_DATES: Date of first request for analysis.
- TestType_REPORT_DATES: Date of first report of analysis
Beyond these, some of the forensic test types had additional associated variables. Other variables include basic background information for each reported crime (case) such as when and where the crime occurred, demographic information (age, gender, and race) on both victim and arrestee, and the disposition of the case (i.e., dismissed, plea agreement, conviction).
Presence of Common Scales View help for Presence of Common Scales
None
HideOriginal Release Date View help for Original Release Date
2022-03-16
Version History View help for Version History
2022-03-16 ICPSR data undergo a confidentiality review and are altered when necessary to limit the risk of disclosure. ICPSR also routinely creates ready-to-go data files along with setups in the major statistical software formats as well as standard codebooks to accompany the data. In addition to these procedures, ICPSR performed the following processing steps for this data collection:
- Checked for undocumented or out-of-range codes.
Notes
The public-use data files in this collection are available for access by the general public. Access does not require affiliation with an ICPSR member institution.
One or more files in this data collection have special restrictions. Restricted data files are not available for direct download from the website; click on the Restricted Data button to learn more.