Human Factors Psychology Commons^™

Assessment Of Bias In Police Lineups., Nancy K. Steblay, Gary L. Wells

Faculty Authored Articles

Materials from five extant field studies were analyzed to determine the level of structural bias in police lineups. Depending on the jurisdiction, between 33% and 68% of lineups sampled from 1,548 real police lineups scored as suspect-biased using mock-witness proportion score. The suspect did not draw a fair portion of mock-witness picks in 20% of field lineups (reverse-biased lineups). Lineup fairness measures revealed that a point estimate (mean) for a set of lineups can mask significant problems in lineup construction and that any single lineup should not be assumed to be fair based on an aggregate score. A sample of …