Pitfalls in using eyewitness confidence to diagnose the accuracy of an individual identification decision.

Abstract

Recently, a number of authors have made strong claims about the likely very high accuracy of identifications made with very high levels of confidence when identification testing conditions are pristine. We argue that although these strong claims about the confidence–accuracy relation are justifiable at the aggregate level, they may be misleading when attempting to evaluate the accuracy of an individual identification. First, we consider the recent evolution of conclusions drawn about the confidence–accuracy relationship, and the implications of these conclusions for the utility of confidence for evaluating individual identifications. Next, we highlight factors that may undermine the generalizability of conclusions at the aggregate level to individual cases. Finally, we present reanalyses of published data demonstrating conditions where conclusions based on aggregate data would be misleading for practitioners evaluating an individual identification. We maintain that, when appropriately collected, confidence can be a useful guide when assessing the reliability of identifications. However, we argue that when police and triers of fact attempt to evaluate the likely accuracy of an individual identification decision it will often be impossible to know if one of the key prerequisites for assessing whether a high confidence identification indicates an accurate identification - namely, a fair lineup - has been met.