Nancy K. Steblay

Eyewitness Accuracy Rates in Sequential and Simultaneous Lineup Presentations: A Meta-Analytic Comparison

Most police lineups use a simultaneous presentation technique in which eyewitnesses view all lineup members at the same time. Lindsay and Wells (R. C. L. Lindsay & G. L. Wells, 1985) devised an alternative procedure, the sequential lineup, in which witnesses view one lineup member at a time and decide whether or not that person is the perpetrator prior to viewing the next lineup member. The present work uses the technique of meta-analysis to compare the accuracy rates of these presentation styles. Twenty-three papers were located (9 published and 14 unpublished), providing 30 tests of the hypothesis and including 4,145 participants. Results showed that identification of perpetrators from target-present lineups occurs at a higher rate from simultaneous than from sequential lineups. However, this difference largely disappears when moderator variables approximating real world conditions are considered. Also, correct rejection rates were significantly higher for sequential than simultaneous lineups and this difference is maintained or increased by greater approximation to real world conditions. Implications of these findings are discussed.

Eyewitness accuracy rates in police showup and lineup presentations: a meta-analytic comparison.

Meta-analysis is used to compare identification accuracy rates in showups and lineups. Eight papers were located, providing 12 tests of the hypothesis and including 3013 participants. Results indicate that showups generate lower choosing rates than lineups. In target present conditions, showups and lineups yield approximately equal hit rates, and in target absent conditions, showups produce a significantly higher level of correct rejections. False identification rates are approximately equal in showups and lineups when lineup foil choices are excluded from analysis. Dangerous false identifications are more numerous for showups when an innocent suspect resembles the perpetrator. Function of lineup foils, assessment strategies for false identifications, and the potential impact of biases in lineup practice are suggested as additional considerations in evaluation of showup versus lineup efficacy.

Eyewitness Identification Reforms Are Suggestiveness-Induced Hits and Guesses True Hits?

Research-based reforms for collecting eyewitness identification evidence (e.g., unbiased pre-lineup instructions, double-blind administration) have been proposed by psychologists and adopted in increasing numbers of jurisdictions across the United States. It is well known that reducing rates of mistaken identifications can also reduce accurate identification rates (hits). But the reforms are largely designed to reduce the suggestiveness of the procedures they are meant to replace. Accordingly, we argue that it is misleading to label any hits obtained because of suggestive procedures as “hits” and then saddle reforms with the charge that they reduce the rate of these illegitimate hits. Eyewitness identification evidence should be based solely on the independent memory of the witness, not aided by biased instructions, cues from lineup administrators, or the use of lineup fillers who make the suspect stand out. Failure to call out these hits as being illegitimate can give solace to those who are motivated to preserve the status quo.

What We Know Now: The Evanston Illinois Field Lineups

A Freedom of Information Act lawsuit secured 100 eyewitness identification reports from Evanston, Illinois, one of three cities of the Illinois Pilot Program. The files provide empirical evidence regarding three methodological aspects of the Program’s comparison of non-blind simultaneous to double-blind sequential lineups. (1) A-priori differences existed between lineup conditions. For example, the simultaneous non-blind lineup condition was more likely to involve witnesses who had already identified the suspect in a previous lineup or who knew the offender (non-stranger identifications), and this condition also entailed shorter delays between event and lineup. (2) Verbatim eyewitness comments were recorded more often in double-blind sequential than in non-blind simultaneous lineup reports (83% vs. 39%). (3) Effective lineup structure was used equally in the two lineup conditions.

Sequential Lineup Laps and Eyewitness Accuracy

Police practice of double-blind sequential lineups prompts a question about the efficacy of repeated viewings (laps) of the sequential lineup. Two laboratory experiments confirmed the presence of a sequential lap effect: an increase in witness lineup picks from first to second lap, when the culprit was a stranger. The second lap produced more errors than correct identifications. In Experiment 2, lineup diagnosticity was significantly higher for sequential lineup procedures that employed a single versus double laps. Witnesses who elected to view a second lap made significantly more errors than witnesses who chose to stop after one lap or those who were required to view two laps. Witnesses with prior exposure to the culprit did not exhibit a sequential lap effect.

All is not as it seems: Avoidable pitfalls in the interpretation of lineup field data.

Archival data from a Chicago field study were examined to determine how lineup structure, presentation, and documentation may unfold in police cases and to consider the uses or pitfalls of field data for evaluating lineup procedure (system factor) effectiveness. A primary question concerned the anomalous low rate of filler selections by eyewitnesses for Chicago lineups. These data alert researchers to 2 primary pathways for distortion of descriptive archival data. Biased lineup procedures (lineup structure and presentation) can move witnesses toward the suspect. Biased documentation can enhance reports that maintain the police presumption of the suspect-as-perpetrator. Both processes will diminish the precision and validity of lineup evidence and undermine evaluation of system variable effectiveness in police practice.