What does consistency reveal about credibility? Four meta-analyses

Inconsistency is often viewed as a sign of deception, whereas consistency is taken as evidence of credibility. However, experts disagree on the extent to which consistency cues can inform credibility judgments. We conducted meta-analyses on four types of consistency (within-statement, between-statement, within-group, and statement-evidence), based on 257 effect sizes from 52 studies involving approximately 4370 participants. Moderator analyses examined factors such as delay between statements, rehearsal opportunities, interviewing methods, and timing of evidence disclosure. For within-statement consistency, we found some evidence that liars showed more inconsistencies than truth-tellers, but the effect was small, fragile, and driven mainly by rare contradictions (g = 0.22, p = .026, BF10 = 1.90). For between-statement consistency, results strongly supported the null hypothesis: liars were as consistent as truth‑tellers (g = 0.05, p = .570, BF01 = 9.69). For within-group consistency, we found no significant evidence that liars were less consistent than truth-tellers (g = 0.39, p = .242), but also no conclusive evidence for the null hypothesis (BF01 = 1.43). For statement-evidence consistency, we found a large significant effect and extreme evidence that liars were less consistent than truth-tellers (g = 1.38, p < .001, BF10 = ∞), particularly when evidence was disclosed late or gradually rather than early. We identify gaps in the literature and recommend future research using more ecologically valid paradigms and more transparent coding, as well as distinguishing central from peripheral inconsistencies. These findings may help legal professionals make better-informed judgments about the credibility of statements based on consistency.