An evaluation of an abbreviated version of a checklist to aid judgements of credibility in the medico-legal setting

This study investigated a 9-item version of an existing 28-item checklist which improved inter-viewers’ classification of interviewees who were truth tellers and interviewees who were exaggerating their symptoms. Eighty-eight adult participants made a credibility judgement based on a video-recorded interview of subjects following an ice plunge experience. Evaluators, using an abbreviated checklist or no checklist, performed at a level no better than chance. Those using the full checklist achieved an overall hit rate significantly higher than chance level (86% overall accuracy with 100% accuracy for truth tellers and 73% accuracy for exaggerators). Results confirmed that the original checklist improved the ability of evaluators to distinguish between truth tellers and exaggerators, while reduction of the checklist reduced its utility. Lens modelling highlighted the five items that were most able to aid in the accurate detection of a malingering interviewee.