Criminal Justice Implications of Forensic Evidence: Assessing Its Significance in Determining Guilt

Abstract

Recent research has indicated that the general public frequently perceives forensic evidence as prone to inaccuracies and dependent on substantial subjective interpretation. By contrasting the reliability of forensic evidence with that of eyewitness testimony in criminal cases and testing for the existence of a "CSI effect," this study explores the public's perception of the relevance of this type of evidence. In this specific survey experiment, participants were assigned randomly to one of seven vignette scenarios. These scenarios were created using a design matrix with three factors: crime type (murder or rape), evidence type (DNA or fingerprint), and the presence or absence of victim and bystander eyewitness testimony (with the exception of the murder scenario, which had no victim testimony). The results indicate that the presence of forensic evidence increases the likelihood of a guilty judgment and the conviction rate. There was no change in either the expected or intended sentence duration as a result of including forensic evidence. Respondents predicted a longer sentence for a rape offender when forensic evidence was presented. However, this did not lead to any changes in their expectations regarding the likely punishment for the defendant. The investigation did not uncover any evidence of a CSI effect. In general, the findings indicate that forensic evidence, especially DNA, tends to have a greater impact on influencing judgments rather than influencing sentencing decisions.