'Immunising' physicians against availability bias in diagnostic reasoning: A randomised controlled experiment

Sílvia Mamede*, Sílvia Mamede*, Marco Antonio De Carvalho-Filho, Marco Antonio De Carvalho-Filho, Rosa Malena Delbone De Faria, Rosa Malena Delbone De Faria, Daniel Franci, Maria Do Patrocinio Tenorio Nunes, Ligia Maria Cayres Ribeiro, Julia Biegelmeyer, Laura Zwaan, Henk G. Schmidt

*Corresponding author for this work

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29 Citations (Scopus)
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Background Diagnostic errors have often been attributed to biases in physicians' reasoning. Interventions to ' immunise' physicians against bias have focused on improving reasoning processes and have largely failed. Objective To investigate the effect of increasing physicians' relevant knowledge on their susceptibility to availability bias. Design, settings and participants Three-phase multicentre randomised experiment with second-year internal medicine residents from eight teaching hospitals in Brazil. Interventions Immunisation: Physicians diagnosed one of two sets of vignettes (either diseases associated with chronic diarrhoea or with jaundice) and compared/contrasted alternative diagnoses with feedback. Biasing phase (1 week later): Physicians were biased towards either inflammatory bowel disease or viral hepatitis. Diagnostic performance test: All physicians diagnosed three vignettes resembling inflammatory bowel disease, three resembling hepatitis (however, all with different diagnoses). Physicians who increased their knowledge of either chronic diarrhoea or jaundice 1 week earlier were expected to resist the bias attempt. Main outcome measurements Diagnostic accuracy, measured by test score (range 0-1), computed for subjected-to-bias and not-subjected-to-bias vignettes diagnosed by immunised and not-immunised physicians. Results Ninety-one residents participated in the experiment. Diagnostic accuracy differed on subjected-to-bias vignettes, with immunised physicians performing better than non-immunised physicians (0.40 vs 0.24; difference in accuracy 0.16 (95% CI 0.05 to 0.27); p=0.004), but not on not-subjected-to-bias vignettes (0.36 vs 0.41; difference-0.05 (95% CI-0.17 to 0.08); p=0.45). Bias only hampered non-immunised physicians, who performed worse on subjected-to-bias than not-subjected-to-bias vignettes (difference-0.17 (95% CI-0.28 to-0.05); p=0.005); immunised physicians' accuracy did not differ (p=0.56). Conclusions An intervention directed at increasing knowledge of clinical findings that discriminate between similar-looking diseases decreased physicians' susceptibility to availability bias, reducing diagnostic errors, in a simulated setting. Future research needs to examine the degree to which the intervention benefits other disease clusters and performance in clinical practice. Trial registration number 68745917.1.1001.0068.

Original languageEnglish
Pages (from-to)550-559
Number of pages10
JournalBMJ Quality & Safety
Issue number7
Publication statusPublished - 18 Jun 2020

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