Overconfidence, Time-on-Task, and Medical Errors: Is There a Relationship?

Background: Literature suggest that physicians' high level of confidence has a negative impact on medical decisions, and this may lead to medical errors. Experimental research is lacking; however, this study investigated the effects of high confidence on diagnostic accuracy. Methods: Forty internal medicine residents from different hospitals in Saudi Arabia were divided randomly into two groups: A highconfidence group as an experimental and a low-confidence group acting as a control. Both groups solved each of eight written complex clinical vignettes. Before diagnosing these cases, the high-confidence group was led to believe that the task was easy, while the lowconfidence group was presented with information from which it could deduce that the diagnostic task was difficult. Level of confidence, response time, and diagnostic accuracy were recorded. Results: The participants in the high-confidence group had a significantly higher confidence level than those in the control group: 0.75 compared to 0.61 (maximum 1.00). However, neither time on task nor diagnostic accuracy significantly differed between the two groups. Conclusion: In the literature, high confidence as one of common cognitive biases has a strong association with medical error. Even though the high-confidence group spent somewhat less time on the cases, suggesting potential premature decision-making, we failed to find differences in diagnostic accuracy. It is suggested that overconfidence should be studied as a personality trait rather than as a malleable characteristic.