What does consistency reveal about credibility?

During the Ghislaine Maxwell trial, defense attorneys focused heavily on inconsistencies in a key witness’s statements, treating them as signs of unreliability. The courtroom exchange reflects a widespread belief in law and everyday life: inconsistent stories signal lying, while consistency equals credibility.

A new preprint by Annelies Vredeveldt, Eva van Rosmalen, Sera Wiechert and Bruno Verschuere puts that belief to a comprehensive test. They conducted four meta-analyses spanning 52 studies and more than 4,300 participants, examining different kinds of consistency: within a single statement, between repeated statements, between multiple witnesses, and between statements and physical evidence.

Their findings challenge many common assumptions: most types of inconsistencies are not reliable signs of deception. Liars are no more inconsistent than truth-tellers when stories are repeated over time or compared across people. Even within a single statement, the differences are small and fragile, driven mainly by rare, clear contradictions.

There is one important exception. When statements conflict with independent physical or documentary evidence, inconsistencies are a strong sign of deception. This is especially true when the evidence is not disclosed right at the beginning of the interview.

The public significance is clear. Police investigators, lawyers, judges and journalists often overinterpret everyday inconsistencies, risking serious errors when the stakes are high. A more evidence-based understanding of consistency can lead to fairer credibility judgments and better-informed decisions.

The preprint can be read here: https://osf.io/preprints/psyarxiv/y97xg_v1