A meta-analysis of confidence and judgment accuracy in clinical decision making.

The overconfidence bias occurs when clinicians overestimate the accuracy of their clinical judgments. This bias is thought to be robust leading to an almost universal recommendation by clinical judgment scholars for clinicians to temper their confidence in clinical decision making. An extension of the Meta-Analysis of Clinical Judgment (Spengler et al., 2009) project, the authors synthesized over 40 years of research from 36 studies, from 1970 to 2011, in which the confidence ratings of 1,485 clinicians were assessed in relation to the accuracy of their judgments about mental health (e.g., diagnostic decision making, violence risk assessment, prediction of treatment failure) or psychological issues (e.g., personality assessment). Using a random effects model a small but statistically significant effect (r = .15; CI = .06, .24) was found showing that confidence is better calibrated with accuracy than previously assumed. Approximately 50% of the total variance between studies was due to heterogeneity and not to chance. Mixed effects and meta-regression moderator analyses revealed that confidence is calibrated with accuracy least when there are repeated judgments, and more when there are higher base rate problems, when decisions are made with written materials, and for earlier published studies. Sensitivity analyses indicate a bias toward publishing smaller sample studies with smaller or negative confidence-accuracy effects. Implications for clinical judgment research and for counseling psychology training and practice are discussed.