Accepting diagnostic suggestions by residents: a potential cause of diagnostic error in medicine.

Background: Psychological research has shown that people tend toward accepting rather than refuting hypotheses. Diagnostic suggestions may evoke such confirmatory tendencies in physicians, which may lead to diagnostic errors. Purpose: This study investigated the influence of a suggested diagnosis on physicians' diagnostic decisions on written clinical cases. It was hypothesized that physicians would tend to go along with the suggestions and therefore would have more difficulty rejecting incorrect suggestions than accepting correct suggestions. Methods: Residents (N = 24) had to accept or reject suggested diagnoses on 6 cases. Three of those suggested diagnoses were correct, and 3 were incorrect. Results: Results showed the mean correct evaluation score on cases with a correct suggested diagnosis (M = 2.21, SD = 0.88) was significantly higher than the score on cases with an incorrect suggested diagnosis (M = 1.42, SD = 0.97), meaning physicians indeed found it easier to accept correct diagnoses than to reject incorrect diagnoses, t(23) = 2.74, p < .05, d = .85, despite equal experience with the diagnoses. Conclusion: These findings indicate that suggested diagnoses may evoke confirmatory tendencies and consequently may lead to diagnostic errors.