A quality assurance committee is establishing best practices for ordering various laboratory and imaging studies in an emergency department. They find that one physician orders significantly more CT scans of the head compared to other physicians in the department. The physician states that he orders more head CT scans on young patients with chronic migraines, even those with normal examination and unremarkable history, because he recently missed a diagnosis of intracranial bleed in an 18-year old patient with a history of chronic migraines. Which of the following most likely explains this physician's tendency to now order excessive CT scans of the head?
Common cognitive errors in medicine | ||
Type of bias | Definition | Example |
Anchoring |
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Availability |
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Confirmation |
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Framing |
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Cognitive errors are unconscious biases adversely influencing clinical judgment and leading to diagnostic error. They often involve heuristics, mental shortcuts formed based on patterns and learned associations. Heuristics represent fast, unconscious thinking (eg, impulse) rather than measured, rational analysis; physicians who are fatigued or who work in busy clinical settings are more likely to rely on heuristics to increase diagnostic efficiency.
This physician started ordering unnecessary head CT scans after missing a diagnosis of intracranial bleed; this behavior reflects availability bias. Availability bias (or "recency effect") occurs when a memorable ("high-stakes"), often recent case biases subsequent judgment and decision-making. This physician's recent experience created a mental heuristic to order head CT scans on patients with migraines. As seen in this scenario, availability bias commonly causes excessive diagnostic workup and overtreatment.
Cognitive bias can be minimized by increasing physician awareness (eg, morbidity and mortality meetings), encouraging systematic analysis (eg, quick-access electronic tools to calculate pre-test probability), and optimizing the environment (eg, additional staff to reduce physician burden).
(Choice B) Data misinterpretation, a cause of diagnostic error, may result from cognitive bias. For example, confirmation bias can result in overlooking potentially concerning information on imaging or laboratory data in a patient with headache. Data misinterpretation and confirmation bias may have triggered the physician's initial missed diagnosis in the patient with migraine. However, his tendency to subsequently order CT scans on low-risk patients with headache reflects availability bias.
(Choice C) Documentation error involves inaccurate or incomplete record-keeping (eg, not documenting pertinent physical examination findings, copy-and-pasting outdated information). Documentation is not a contributing factor in this scenario.
(Choice D) Knowledge deficiency (eg, insufficient ability to interpret clinical data) is a rarer cause of diagnostic error for practicing physicians compared with cognitive error. This physician's behavior started after a recent patient experience; therefore, knowledge deficiency regarding head CT imaging indications is unlikely.
Educational objective:
Cognitive errors involve heuristics (mental shortcuts) incorrectly influencing clinical decision-making, resulting in diagnostic error. Availability bias describes the tendency for recent or notable clinical experiences to bias subsequent clinical judgment, and often causes excessive diagnostic workup.