Why we still use our heads instead of formulas: toward an integrative approach.

This review begins with a discussion of Meehl's (1957) query regarding when to use one's head (i.e., intuition) instead of the formula (i.e., statistical or mechanical procedure) for clinical prediction. It then describes the controversy that ensued and analyzes the complexity and contemporary relevance of the question itself. Going beyond clinical inference, it identifies select cognitive biases and constraints that cause decision errors, and proposes remedial correctives. Given that the evidence shows cognition to be flawed, the article discusses the linear regression, Bayesian, signal detection, and computer approaches as possible decision aids. Their cost-benefit trade-offs, when used either alone or as complements to one another, are examined and evaluated. The critique concludes with a note of cautious optimism regarding the formula's future role as a decision aid and offers several interim solutions.