The Doctor's Dilemma

By Howard Marcus, MD, FACP

The Doctors Company Internal Medicine Closed Claims Study analyzed 1,180 claims that closed from 2007-2014. The study found that the top allegation, representing 39 percent of claims against internists, was diagnosis related and resulted from a delay or failure to diagnose.

Physicians fail to diagnose accurately for many reasons. The dilemma can be understood best in the context of the complexity of clinical medicine. Illnesses present with an infinite number of variations, illustrated by the 68,000 ICD-10 diagnostic codes and 8,000 recognized diseases and syndromes -- many of which are uncommon.

It is in this context that failure to diagnose may be viewed as an error or lapse in reasoning rather than just a failure of clinical skill. Therefore, diagnostic accuracy can be improved with a better understanding of how to avoid pitfalls in medical decision making.

The monograph Improving Diagnosis in Health Care characterizes failure to diagnose in terms of two types of thinking processes -- rapid and slow -- and the effects of psychological biases on medical decision making.

Type I, or rapid decision making, involves pattern recognition (heuristics) that allows the clinician to successfully diagnose and treat most patients efficiently.

Type II, or slow decision making, requires recognition by the clinician of the possibility of a complex medical problem and the need for careful thought, a differential diagnosis, lab and imaging studies, reference resources, and/or consultation with a specialist. Recognition of risk factors is essential.

Psychological biases may undermine accurate diagnosis and treatment. Some common examples include the following:

  • Anchoring bias: The tendency to rely too heavily on, or "anchor" to, one trait or piece of information when making decisions -- usually the first piece of information or diagnosis that is acquired.
  • Premature closure: The tendency to apply premature closure to the decision-making process by accepting a diagnosis or treatment before it has been fully verified.
  • Overconfidence bias: A universal tendency to believe we know more than we do.
  • Optimism bias: The tendency to be overly optimistic by overestimating favorable and pleasing outcomes. This can also be considered a form of denial.

The following illustration is taken from The Doctors Company Internal Medicine Closed Claims Study.

A 65-year-old female presented with nausea, fever, and a dark area in the visual field of the right eye. She was diagnosed with a viral infection. Four days later, she presented to an ophthalmologist with the loss of central vision in the right eye and was diagnosed with a retinal detachment, resulting in permanent loss of vision.

Primary care physicians see many patients with nonspecific symptoms of nausea and fever. Most of these patients have an acute and self-limited viral illness. However, complaints of acute visual loss are relatively uncommon in a general practice, and most primary care physicians do not have the training or equipment to properly evaluate those patients. This case illustrates overconfidence bias in which the physician appears to have failed to recognize the potential significance of an unusual visual complaint, concentrating instead on the more common viral illness.

Read the full study, including expanded case examples and risk mitigation strategies, at

Contributed by The Doctors Company. For more patient safety articles and practice tips, visit


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