SEQUENTIAL VS. SIMULTANEOUS LINEUPS: A Review of Methods, Data, and Theory

A considerable amount of empirical research has been conducted on ways to improve the eyewitness identification process, with emphasis on the use of lineups. Public policy changes are currently underway with respect to lineup procedures: Sequential lineups are being recommended to police as the best practice. This may be premature because the conditions under which sequential lineups are superior to simultaneous lineups are not well understood given the current literature: Many studies are reported with insufficient detail needed to judge the adequacy of the research design, new data show that the sequential superiority effect may vary as a function of study methodology, theoretical assumptions have not been adequately tested, and important comparisons that may rule out the ostensible superiority of the sequential lineup have not been studied. This review summarizes the literature, presents new data, and identifies the need for further empirical work before appropriately grounded recommendations as to the superiority of sequential lineups can be made.