What price justice? Exploring the relationship of lineup fairness to identification accuracy.

Doob and Kirshenbaum (1973) and Wells, Leippe, and Ostrom (1979) demonstrated that some real-world lineups have been constructed such that the suspect can be identified by mock witnesses given only a general description of the criminal. The authors of both studies suggest that “fair” lineups should contain foils that resemble the suspect in general physical appearance. Neither study considers the possible cost of such “fair” lineups in terms of lost convictions of guilty suspects. A staged crime paradigm was used to evaluate the costs and benefits of “fair” lineups. Unsuspecting witnesses (n=96) to a staged crime were given the opportunity to identify a criminal (confederate) from relatively fair or unfair lineups (six-picture arrays, varying high versus low foil similarity). One fair and one unfair lineup contained a picture of the criminal (criminal-present lineups) while one fair and one unfair lineup contained a picture of an innocent suspect who resembled the criminal (criminal-absent lineups). In the criminal justice system only identifications of the criminal or the innocent suspect lead to further proceedings. The results indicate that high-similarity lineups produced less identifications of the criminal and of the innocent suspect than low-similarity lineups. However, the reduction in identifications of the criminal was much less dramatic than the reduction of identifications of the innocent suspect. A Bayesian analysis (Wells & Lindsay, 1980) of the data led to the further conclusion that identification evidence obtained from relatively fair high-similarity lineups is superior to similar evidence obtained from relatively unfair low-similarity lineups. The cost (in lost convictions of guilty suspects) of using fair lineups (high foil similarity) appears to be rather small.