Putting the Microscope on Crime Labs: The Effects of Evidence Complexity and Laboratory Type on Jurors\u27 Perceptions of Forensic Evidence

An experiment was conducted to test the effects of evidence complexity and laboratory type on jurors\u27 perceptions of forensic evidence. The study specifically focused on three types of labs: public labs, private labs, and corporate labs. Public labs are managed by a federal, state, or local law enforcement agency, where evidence is usually analyzed internally at an agency. Private labs are those that have been formed as private businesses to provide services to federal, state, and local crime labs with overflow work. Corporate labs are managed by major retail corporations, and primarily service the needs of their store businesses, but also assist federal, state, and local agencies with overflow work and specialized cases. A national sample of mock jurors was presented with latent fingerprint evidence analyzed at 1 of the 3 types of crime labs. Evidence was presented in either a high-complexity (i.e., unfamiliar scientific language) or low-complexity (i.e., lay terms) format. Both lab type and evidence complexity were found to have significant effects on perceptions of evidence and verdict decisions. The findings are considered in the context of persuasion theories, and have implications in terms of developing best practice guidelines for forensic evidence presentation in court