Psychology, Public Policy, and Law, Vol 31(1), Feb 2025, 22-30; doi:10.1037/law0000432
The Considering Offender Probability Statements (COPS) scale is a checklist designed to discern caller deception in 911 homicide calls. The current study evaluated the scale’s ability to distinguish between false allegation callers and true report callers using a data set of one hundred 911 homicide calls. Results indicated an inability of the COPS scale to differentiate false allegation callers from true report callers, casting doubt on its discriminative ability. Further scrutiny of the individual items of the COPS scale revealed discrepancies, with certain items contradicting the scale’s expected outcomes. Moreover, a review of effect sizes from past studies, including those by the scale’s creators and independent researchers, indicated potential issues in the initial research by the COPS scale’s creators. This was evidenced by the consistently lower effect sizes reported in independent studies and by effect sizes that seemed improbable by the COPS scale creators. These results underscore the need for more comprehensive, empirically backed methods in the development of deception detection tools. They also emphasize the critical need for collaborative endeavors in enhancing and substantiating these tools before law enforcement agencies use them in criminal investigations. (PsycInfo Database Record (c) 2025 APA, all rights reserved)