Validity of mock-witness measures for assessing lineup fairness

ABSTRACT

Although eyewitness researchers have used mock-witness measures to assess aspects of lineup fairness, they have paid little attention to their validity. The current study tested predictive validity, convergent validity, and discriminant validity of mock-witness measures from a meta-analytic perspective. Overall, mock-witness measures had predictive validity, particularly in target-absent (TA) lineups – the lineup fairness estimated by the measures reliably predicted eyewitnesses’ choosing behaviors and discriminability of a suspect from fillers in TA lineups. However, correlations between lineup fairness estimated by mock-witnesses and eyewitness performance were significant in target-present (TP) lineups only when eyewitnesses had a moderate memory for the perpetrator. Multitrait-multimethod correlations demonstrated significant intradomain correlations between mock-witness measures and other lineup fairness indices and nonsignificant interdomain correlations between the mock-witness measures and indices reflecting memory strength for the perpetrator, which supported convergent validity and discriminant validity, respectively. The implications for research and practice are discussed.

KEYWORDS:

• Mock witness
• mock-witness paradigm
• eyewitness
• lineup fairness
• lineup bias

Disclosure statement

No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Notes

1 Note that there is a dependency in these analyses to the extent that the lineup fairness measures are sometimes based on responses to the same mock crime/lineup materials. This can be true both when multiple measures are obtained from a single study or publication and when researchers use the same materials across studies or publications.

Additional information

Funding

The present study is based upon work supported by the Division of Social and Economic Sciences under grant number SES-1754079. Any opinion, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation.