Best Practices at Police Lineups

Title: Reduction of False Convictions through Improved Identification Procedures: Further Refinements for Street Practice and Public Policy (pdf, 92 pages)

Author: Nancy K. Steblay

Abstract:

The purpose of this project was to enhance the quality and value of eyewitness evidence acquired through police lineups. Objectives were to:

1.            conduct a review of research comparing simultaneous with sequential lineup procedures;

2.            evaluate the sequential superiority effect and moderators of this effect; and

3.            conduct controlled lab tests of factors that impact the eyewitness accuracy of police lineup procedures by: relaxing the Yes/No response requirement of the sequential lineup procedure to allow for“I’m not sure” responses, providing appearance change instruction to the eyewitnesses, and discouraging multiple identification tasks in police lineups by the same witness.

Using both a meta-analytic review of research and a field test, the authors found that the sequential lineup format was more effective than simultaneous lineups. Furthermore, new laboratory data demonstrate a positive effect of sequential lineups on eyewitness identification, only minimal impact of an Appearance Change Instruction, and a significant negative effect of repeated lineups.

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