The Impact of Forensic Evidence on Criminal Justice: Evidence from Case Processing Studies

Abstract

Reliance on forensic evidence (FE) in police investigations and court trials has increased rapidly over the past 20 years. Traditionally, FE was used mainly to corroborate evidence (Bradbury & Feist, 2005); however, FE is increasingly becoming influential in focusing the direction of police investigations (Julian, Kelty, & Robertson, 2012) and in exonerating the innocent (Sangha, Roach, & Moles, 2010). The increased use of FE in investigations and the courts is evident in the fourfold increase over 40 years in the number of forensic laboratories and the rapid growth in more sophisticated techniques to analyze FE (Peterson et al., 2012). Coinciding with the rise in the use of FE is a widespread belief that recent developments in forensic science, especially DNA, have the ability of law enforcement to identify and prosecute offenders (Dunsmuir, Tran, & Wetherburn, 2008). Despite this belief, what evidence is there that forensic science has in fact revolutionized law enforcement’s ability to process criminal cases more effectively? Recently, a growing number of studies have assessed the impact of FE in the criminal justice system (CJS), but there is still limited empirical research on how effective FE can be on the solvability of serious crime (crimes against the person, such as homicide, rape, and assault) and volume crime (crimes against property, such as burglary and criminal damage) (Julian et al., 2011). In this chapter, the impact of FE on criminal justice outcomes is explored. Part one is a review of the current state of knowledge in this area from the United States, United Kingdom, and Australasia. In the second part, we present the conceptual framework and case-processing flowchart that map out critical decisions and leakage (attrition) points in the use of FE in homicide cases from a large Australian project. In the final part, we conclude with a brief discussion of the impact of FE on criminal justice outcomes based on some of the findings from this research project.