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Uncharted territory: measuring costs of diagnostic errors outside the medical record
  1. Alan Schwartz1,
  2. Saul J Weiner2,
  3. Frances Weaver3,
  4. Rachel Yudkowsky1,
  5. Gunjan Sharma4,
  6. Amy Binns-Calvey1,
  7. Ben Preyss5,
  8. Neil Jordan6,2
  1. 1Department of Medical Education, University of Illinois, Chicago, Illinois, USA
  2. 2Center for the Management of Complex Chronic Care, US Department of Veteran Affairs, University of Illinois, Chicago, Illinois, USA
  3. 3Center for the Management of Complex Chronic Care, US Department of Veteran Affairs, Stritch School of Medicine, Loyola University, Chicago, Illinois, USA
  4. 4Department of Medicine, University of Illinois, Chicago, Illinois, USA
  5. 5Department of Family Medicine, Northwestern University, Chicago, Illinois, USA
  6. 6Department of Psychiatry & Behavioral Sciences, Institute for Healthcare Studies and Preventive Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
  1. Correspondence to Dr Alan Schwartz, Department of Medical Education, University of Illinois, 808 S Wood St, 986 CME Mail Code 591, Chicago, IL 60612, USA; alansz{at}


Context In a past study using unannounced standardised patients (USPs), substantial rates of diagnostic and treatment errors were documented among internists. Because the authors know the correct disposition of these encounters and obtained the physicians' notes, they can identify necessary treatment that was not provided and unnecessary treatment. They can also discern which errors can be identified exclusively from a review of the medical records.

Objective To estimate the avoidable direct costs incurred by physicians making errors in our previous study.

Design In the study, USPs visited 111 internal medicine attending physicians. They presented variants of four previously validated cases that jointly manipulate the presence or absence of contextual and biomedical factors that could lead to errors in management if overlooked. For example, in a patient with worsening asthma symptoms, a complicating biomedical factor was the presence of reflux disease and a complicating contextual factor was inability to afford the currently prescribed inhaler. Costs of missed or unnecessary services were computed using Medicare cost-based reimbursement data.

Setting Fourteen practice locations, including two academic clinics, two community-based primary care networks with multiple sites, a core safety net provider, and three Veteran Administration government facilities.

Main outcome measures Contribution of errors to costs of care.

Results Overall, errors in care resulted in predicted costs of approximately $174 000 across 399 visits, of which only $8745 was discernible from a review of the medical records alone (without knowledge of the correct diagnoses). The median cost of error per visit with an incorrect care plan differed by case and by presentation variant within case.

Conclusions Chart reviews alone underestimate costs of care because they typically reflect appropriate treatment decisions conditional on (potentially erroneous) diagnoses. Important information about patient context is often entirely missing from medical records. Experimental methods, including the use of USPs, reveal the substantial costs of these errors.

  • Decision making
  • evidence-based medicine
  • health professions education
  • cognitive biases
  • diagnostic errors
  • comparative effectiveness research
  • cost effectiveness
  • health policy
  • health services research
  • mental health

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  • Funding This study was supported by the Veteran Affairs, Health Services Research and Development. The funding organisation had no role in the design and conduct of the study; in the collection, analysis, and interpretation of the data; or in the preparation, review or approval of the manuscript. IIR 04-107.

  • Competing interests Alan Schwartz and Saul Weiner are owners of a company that provides management consulting services to healthcare providers and institutions interested in collecting customer service and performance data using methods employed in this study (unannounced standardised patients). Amy Binns-Calvey is a consultant to the company. They have not received any consulting fees, honorarium, contracts or other payments to date. The remaining authors have no relationships or activities that could appear to have influenced the submitted work.

  • Ethics approval The study was approved by the Institutional Review Board of the University of Illinois at Chicago and Jesse Brown VA Medical Center. It was also approved at IRB affiliates of all sites.

  • Provenance and peer review Not commissioned; externally peer reviewed.