A comprehensive meta-analysis of the comparison question polygraph test

Abstract

We conducted a meta-analysis on the most commonly used forensic polygraph test, the Comparison Question Test. We captured as many studies as possible by using broad inclusion criteria. Data and potential moderators were coded from 138 datasets. The meta-analytic effect size including inconclusive outcomes was 0.69 [0.66, 0.79]. We found significant moderator effects. Notably, level of motivation had a positive linear relationship with our outcome measures. Information Gain analysis of CQT outcomes representing the median accuracy showed a significant information increase over interpersonal deception detection across almost the complete range of base rates. Our results suggest that the CQT can be accurate, that experimental studies are generalizable, and no publication bias was detected. We discussed the limitations of the field research literature and problems within polygraph profession that lower field accuracy. We suggest some possible solutions.