Assessing the Validity of Forensic Decisions Through Interrater Reliability

Arizona State University, Scottsdale AZ

Investigators

Abstract

This project will investigate the reliability and validity of forensic decision making in the context of the technique of fired cartridge case comparison. It does so by examining whether inconclusive forensic decisions result from truly ambiguous physical evidence or from non-evidentiary factors. The project additionally will study whether pattern evidence produced by two different sources is sufficiently distinct to be consistently detected by forensic examiners. The project will employ an experimental approach to test the validity of forensic analyses of fired cartridge cases. Through interrater reliability, the research will assess the tendency for multiple forensic examiners to reach similar conclusions when evaluating the same evidence. The project also will ascertain whether the toolmarks left on fired cartridge cases by two discrete weapons are sufficiently distinct to be detected by different examiners. These comparisons will enable the project to test the validity of pattern matching forensic techniques that necessarily rely on subjective human judgments. As this research addresses issues relevant to a multitude of forensic techniques, it will significantly advance knowledge about the probative value of decision making throughout the forensic sciences. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.