Through the lens of legal professionals: Examining the smallest effect size of interest for eyewitness memory research
Article
Riesthuis, P, Rassin, E, Bücken, C et al. (2025). Through the lens of legal professionals: Examining the smallest effect size of interest for eyewitness memory research
. 10.1177/13657127251357630
Riesthuis, P, Rassin, E, Bücken, C et al. (2025). Through the lens of legal professionals: Examining the smallest effect size of interest for eyewitness memory research
. 10.1177/13657127251357630
Legal psychologists sometimes provide expert witness testimony about eyewitness memory in court. In their testimony, they regularly rely on scientific findings that decision-makers (i.e., jurors, judges) likely assume are practically relevant. However, it is not yet known which effect sizes are large enough to be deemed practically relevant for the courtroom, also known as the smallest effect size of interest (SESOI). One way to estimate the SESOI is to engage stakeholders. In two studies, we recruited 97 legal professionals (e.g., defense lawyers, prosecution lawyers, judges) from the Netherlands and Belgium and presented them with hypothetical scenarios about an unarmed robbery wherein an eyewitness made different types of memory errors (e.g., misremembering a black gun). Then, legal professionals were asked how many of such memory errors they would allow before taking certain legal actions. The majority of legal professionals viewed 1–3 memory errors as practically relevant for legal decisions or actions, but this depended on the type of memory error. A nontrivial number of participants indicated that they would never undertake legal actions after a witness made memory errors. The current studies can guide the challenging task of estimating the SESOI in forensic psychological contexts that may assist future researchers.
