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Letters to the Editor

In Reply to Eichbaum

Norman, Geoffrey PhD; Schmidt, Henk G. PhD; Ilgen, Jonathan S. MD

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doi: 10.1097/ACM.0000000000002797
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We thank Dr. Eichbaum for the opportunity to elaborate on some of the points we raised in our Perspective.

Dr. Eichbaum claims that there is little evidence that errors are caused by knowledge gaps. Actually, several studies demonstrate a relationship between measures of knowledge (indicated by board exam scores) and peer review in practice,1 malpractice claims,2 and coronary care mortality.3 Dr. Eichbaum claims that experience “encompasses the gradual acquisition of complex skills and attributes, such as the metacognitive capacity to monitor and regulate one’s own thinking [and emotions].” Conspicuously absent is evidence to justify this claim. We believe that experience is critically important because it involves a different kind of experiential knowledge, not because it enhances “metacognitive capacity.”

Dr. Eichbaum then takes issue with our reliance on written case protocols, failing to mention that much of the evidence used to argue that cognitive biases cause diagnostic errors is also from written cases. Other evidence of cognitive bias comes from retrospective reviews, but these findings are compromised in that reviewers show zero agreement in identifying such biases, and hindsight bias causes them to systematically overestimate the presence of cognitive bias.4

Faced with the absence of evidence that debiasing strategies have any impact on diagnostic errors, Dr. Eichbaum takes refuge in the claim that “debiasing strategies are … difficult to test under general experimental conditions.” Perhaps that is why he finds it necessary to customize instruction to specific contexts. If physicians have to show specific clinical examples of bias to reduce errors in those contexts, that sounds like knowledge to us.

No doubt this topic could use more research; for the moment, we remain content with Dr. Eichbaum’s tacit admission that there is no evidence debiasing strategies work.

Geoffrey Norman, PhD
Emeritus professor, Department of Health Methodology, Evidence and Impact, McMaster University, Hamilton, Ontario, Canada; [email protected]
Henk G. Schmidt, PhD
Professor, Department of Psychology, Erasmus University, Rotterdam, the Netherlands.
Jonathan S. Ilgen, MD
Associate professor, Department of Emergency Medicine, University of Washington, Seattle, Washington.


1. Tamblyn R, Abrahamowicz M, Dauphinee WD, et al. Association between licensure examination scores and practice in primary care. JAMA. 2002;288:3019–3026.
2. Tamblyn R, Abrahamowicz M, Dauphinee D, et al. Physician scores on a national clinical skills examination as predictors of complaints to medical regulatory authorities. JAMA. 2007;298:993–1001.
3. Norcini JJ, Kimball HR, Lipner RS. Certification and specialization: Do they matter in the outcome of acute myocardial infarction? Acad Med. 2000;75:1193–1198.
4. Zwaan L, Monteiro S, Sherbino J, Ilgen J, Howey B, Norman G. Is bias in the eye of the beholder? A vignette study to assess recognition of cognitive biases in clinical case workups. BMJ Qual Saf. 2017;26:104–110.
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