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Alibi Generation and Discriminability: Improving Innocent Suspects’ Accuracy and Examining Alibi Discriminability

NCJ Number
Date Published
182 pages

This is the report of a study that addressed two problematic issues in criminal investigations: 1) innocent alibi providers are often inaccurate when reporting their alibis; and 2) people are unskilled in discriminating true from deceptive alibis.



Two experiments addressed these two issues. One study examined whether a theory-driven intervention involving preparation time with phone access would improve the accuracy of innocent suspects’ alibis. This study also identified cues to deception that could differentiate honest and deceptive alibi providers. Results of this first study showed that innocent suspects were significantly more likely to produce an accurate alibi when they were allowed either preparation time only (32 percent) or preparation and phone access (51 percent), compared to controls (16 percent). The second study examined whether Preparation with Phone Access and Preparation Only also improve evaluators’ abilities to discriminate honest from deceptive alibi providers. Study 2 conformed to a 3 (Alibi Type: Honest/accurate; Honest/mistaken; Deceptive) x 3 (Interview Approach: Preparation with Phone Access; Preparation Only, Control) mixed design. The findings support the schema disconfirmation model, revealing two interventions that can improve the accuracy of innocent suspects’ alibis without increasing the believability of deceptive alibis. The results also provide the basis for a standardized procedure for the collection of alibi evidence. 11 tables, 58 references, and appended study instruments     

Date Published: January 1, 2021