Diagnostic errors are frequently ascribed to cognitive errors on the part of clinicians. Prominent among these is availability bias, when clinicians choose the most available diagnosis—the first that comes to mind—when faced with a complex diagnostic scenario. In this Dutch study, internal medicine residents were presented with a series of diagnosed cases, then given cases with similar symptoms and asked to record their provisional diagnoses. The investigators did find evidence of availability bias, but also found that asking residents to reflect on their diagnostic process mitigated the effects of availability bias. Diagnostic errors have been termed the next frontier in patient safety, and an AHRQ WebM&M commentary discusses reflective practice and other methods of avoiding cognitive error in diagnosis.