Measuring lineup fairness: Mock witness responses versus direct evaluations of lineups.

Abstract

Measures of lineup fairness typically utilize the responses of mock witnesses who attempt to identify the suspect in a lineup based solely on the physical description given by the eyewitnesses. Many people in the criminal justice system deride or fail to understand the relevance of these mock-witness-based indices. The present study compared several fairness indices derived from college student mock witnesses' responses with fairness measures based on more direct evaluations of lineup usefulness and fairness made by a sample of law officers and by another sample of college students. An overall fairness index derived from the mock witness responses related significantly to the law officers' usefulness and fairness categorizations. In general, usefulness and fairness indices calculated from the three sets of subject-college student mock witnesses, college student evaluators, and law officer evaluators-covaried with each other. The findings support the similarity of student-based, mock witness indices of lineup fairness to the fairness evaluations law officers would make of the same lineups.