Where do diagnostic adverse events come from? In reply.

We thank Dr Lader for his interest in our article and his valuable insights. We agree that there is more to it than just knowledge-based mistakes underlying the occurrence of DAEs. The causes described by Dr Lader constitute plausible reasons that could contribute to the occurrence of DAEs. We agree that evidence-based algorithms should not be followed blindly. Evidence-based algorithms represent the latest scientific findings and are therefore a valuable tool for diagnostic reasoning. However, as they are based on data from a large number of patients, these algorithms are not applicable to every patient and in every situation. It is thus particularly important for physicians to recognize the situations in which algorithms are not applicable. This implies that physicians, while diagnosing a patient, need to be aware of the whole context and should reflect on their thinking at the same time.1 For example, physicians are inclined to only look for data confirming their initial diagnosis. While this is often a good strategy, since it allows focusing on the most important examinations and tests, it sometimes leads to a diagnostic error, in particular when a patient reports symptoms not typical for the underlying disease. While making a diagnosis, physicians are not only bounded by limited cognitive capabilities, typical for the human being, but also by time and other constraints. This implies, and we believe this is in line with Dr Lader’s remarks, that it is particularly important to study diagnostic reasoning in diverse situations with time and other constraints. Although the study that we conducted provided interesting insights in the causes of DAEs, record reviews are limited in revealing more specific causal factors. Our study revealed that coordination between health care professionals and transfer of knowledge played a role in the occurrence of DAEs, but it was not possible to examine those causes in more detail. Further research is needed that focuses on the underlying reasons and mechanisms of why DAEs occur, taking into account the circumstances under which these diagnoses are made, eg, a study proposed by our research group. 2 At the same time, we believe that critical thinking and other metacognitive skills 1 may be incorporated in the medical curriculum. These techniques are used for training in the US army, another field where missing a relevant cue might be fatal. (aut. ref.