Cognitive bias in forensic science: a systematic review

Purpose The growing body of research exploring bias in the decision-making of forensic scientists has reached a critical mass that requires an overall perspective and focused overview. The purpose of this systematic review is to systematically appraise the research on the impact of cognitive bias on forensic examiners and evidence used in court. Design/methodology/approach Relevant search terms (see method) were used to search five databases; APA PsycINFO, Web of Science, PubMed, Scopus and HeinOnline, yielding a total of n = 3,242 records. Investigators were specifically interested in quantitative records examining the impact of bias in forensic experts on decision-making. Findings Most studies were experimental (85.71%), examined contextual information (80%) and analysed latent and footwear prints (37.14%). The narrative synthesis demonstrated that most studies suggested contextual information biases the decision-making of forensic examiners. Other factors including, organisational and personal factors, human and cognitive factors and the brain, reference materials and education and training, were also examined, suggesting a potential role in decision-making. Research limitations/implications The Joanna Briggs Institute appraisal highlighted that while the existing studies have made a strong initial effort to explore bias in forensic decision-making, future research must consistently report effect sizes, have better experimental control and use inferential statistics as well as reporting guidelines (e.g. Strengthening the Reporting of Observational Studies in Epidemiology) and preregistrations to improve internal and external validity. Originality/value Almost a decade has passed since Cooper and Meterko (2019) conducted their seminal review investigating cognitive bias in forensic decision-making. While Cooper and Meterko (2019) provided a foundation, highlighting the influence of cognitive (mostly contextual) bias, on several domains of forensic science, important methodological omissions warrant an updated review. As such, we extended the work of Cooper and Meterko (2019) with an up-to-date search and through the application of contemporary systematic review methods. Specifically, this review was pre-registered with the Open Science Framework, conducted and reported in accordance with PRISMA guidelines and used a formal critical appraisal tool.