Social Science Research on the Role and Impact of Forensic Evidence on the Criminal Justice Process

ILJ proposes to conduct cross-sectional data surveys and longitudinal studies to accomplish NIJ's objectives on the collection, analysis, and use of forensic evidence in the criminal justice process. A first cross-sectional data survey will be to police departments in all 237 cities with populations of more than 100,000 residents. The survey will be conducted in two stages, with the first stage aimed at collecting basic information about forensic evidence data collection and availability of details on the quantity and types of forensic evidence collected. A second stage will be to collect data from those police departments with reliable and available information on forensic evidence.

The second survey will be sent to the approximately 350 publicly funded crime laboratories and will be for the purpose of determining the quantity and types of forensic evidence that they analyze. This survey will ask about the analytical functions for forensic evidence in the crime labs and the caseload and types of evidence analyzed by the labs.

Longitudinal studies will be conducted in Miami, Florida; San Diego, California; and a third city to be determined. During the longitudinal studies, ILJ will collect detailed information on forensic evidence collected and analyzed, and its role in prosecutorial and sentencing decisions. These retrospective studies will be based on Part I Crimes (homicide, rape, robbery, assault, burglary, larceny, and auto theft) that occurred during 2005 in the selected cities. Several focus groups and case studies are included in the tasks for the longitudinal studies.

ILJ proposes a typology of forensic evidence that includes fingerprint evidence, biological evidence, firearms evidence, drug evidence, clothing, trace evidence, and other evidence. The proposal is to analyze the quality of forensic evidence from the viewpoint of probative value; that is, the extent to which forensic evidence provides evidentiary facts. In all the data collection and analysis, forensic evidence collected at the primary scene and all secondary scenes (e.g., autopsies, hospitals, residences, vehicles, and others) will be included.

The study includes implications for policymakers at the federal, state, and local levels. There are likely to be significant implications for police personnel on where to concentrate their crime scene evidence gathering resources and who should be responsible for collection of forensic evidence. Prosecutors and judges should be informed by this study on the importance of forensic evidence in cases and the most effective for analysis and presentation of forensic evidence in criminal cases. ca/ncf