This article reviews a large portion of the literature on juror comprehension of forensic science testimony by expert witnesses to identify common themes, followed by recommendations for future research.
Forensic disciplines that have a solid statistical foundation based on population databases, such as single-source DNA comparison, often report their results with a quantitative measure, such as the Random Match Probability (RMP). This is a means of establishing the likelihood of a coincidental match of a given set of features in a population. This is done to provide jurors with a statistical basis for the weight they give to the expert witness’ forensic findings; however, this literature review found that multiple studies have concluded that laypersons struggle to understand the meaning of the RMP; and in many cases, they concluded the opposite of what the RMP analysis indicated. This literature review also examined some efforts that have been tried to bring the interpretation of the RMP into terms the layperson can understand. The difficulty with many of these efforts is time restraints that do not allow for an education of jurors about the process and interpretation of statistical analyses. Another common finding in the literature reviewed is that jurors will have variable and unreliable conclusions about the relative weight to give expert forensic evidence based on statistical assessments of the reliability of the expert witness’ featured conclusions. The overall theme of suggestions for future research is the need to evaluate the effectiveness and practicality of various methods for enabling jurors to better understand and weight the reliability and significance of expert forensic testimony. 56 references, with online access provided for each listing (publisher abstract modified)