Evaluating lineup fairness: Variations across methods and measures

Area of Science:

• Psychology
• Forensic Science
• Criminal Justice

Background:

• Lineup fairness is crucial for evaluating identification procedures and research consistency.
• Empirical attention to lineup fairness measures and mock-witness tasks is limited and inconsistently reported.

Purpose of the Study:

• To investigate how lineup fairness measures are affected by mock-witness task methodologies.
• To explore the validity and reliability of different lineup fairness measures.

Main Methods:

• A large-scale online experiment with 1,010 participants.
• Comparison of lineup fairness measures using individual versus aggregated witness descriptions in mock-witness tasks.

Main Results:

• Individual descriptions led to higher perceived plausible lineup members but increased suspect bias compared to aggregated descriptions.
• Target-absent lineups were rated fairer than target-present lineups, potentially masking bias against innocent suspects.
• Measures showed convergent and discriminant validity, but reliability varied across descriptions and mock witnesses.

Conclusions:

• Mock-witness task methodology significantly impacts lineup fairness perceptions.
• Current fairness measures may inaccurately suggest that lineups with innocent suspects are less biased.
• Standardized reporting of description type, detail, and lineup conditions is essential for future research.