Are Cognitive Biases Influencing Your Clinical Decisions?

Diagnostic errors occur for many reasons, some of which are based in cognitive biases. Also called cognitive dispositions to respond (CDR), these can result from failures in perception, faulty mental shortcuts, or unconscious biases, and clinicians are usually unaware they exist. This article discusses the influence CDRs have on clinical decisions and walks you through methods for purposeful debiasing.

Diagnosis is the foundation of medicine ... [and] diagnostic reasoning is a critical aspect of clinical performance.¹
— Pat Croskerry, MD, PhD

Diagnostic errors compromise patient safety and the quality of health care and account for the majority of paid malpractice claims. They are especially common in family medicine, internal medicine, emergency medicine, and urgent care, wherethe error rate can be as high as 15%.² However, all health care providers are subject to errors in clinical judgment, regardless of the setting or specialty in which they practice.³

Clinical disciplines such as internal medicine and emergency medicine have higher error rates than the perceptual disciplines, radiology and pathology. Higher diagnostic error rates in the clinical disciplines are due to the elevated case complexity and the need for rapid interpretation of diagnostic studies. In the perceptual disciplines such as pathology and radiology, fewer time pressures and the ability to obtain a second opinion before making a diagnosis decrease error rates.³ In a National Practitioner Data Bank analysis, more diagnostic error claims occurred in the outpatient setting than in the inpatient setting.⁴

Quality assurance and performance improvement have become paramount for all health care providers. The modern patient safety movement began in 1999 with the Institute of Medicine (IOM) report To Err Is Human, which highlighted how a faulty health care system causes people to make mistakes and negatively impacts patient safety.⁵ Some examples of errors arising from imperfections in the health system include medication errors, patient falls, wrong-site surgeries, and improper patient identification. Despite an increased emphasis on patient safety and quality improvement, diagnostic error had not been a focus of attention for policy makers and institutions. Only since the IOM report was released have the medical profession and health policy makers begun to pay attention to diagnostic errors as a serious patient safety issue.⁵

Cognitive biases, or cognitive dispositions to respond (CDR), can influence clinical decision-making and lead to diagnostic errors. By understanding the thinking processes involved in diagnostic reasoning and the interaction between these processes and cognitive biases, clinicians can take steps to counteract the influence of cognitive biases on their clinical decisions. Here, a brief introduction to dual processing theory is provided, along with information to help clinicians identify potential cognitive biases. Workplace and educational debiasing techniques to counter biases that lead to cognitive decision errors are presented as well.

DIAGNOSTIC ERRORS
All advanced practice providers are at risk for making a clinical decision error. The diagnostic errors that are made in clinical practice can be classified into three broad etiologic categories⁶:

No-fault errors occur when a rare disease is misdiagnosed as something more common or a disease is silent or presents in an atypical manner. An example of an error that falls into this category is a delayed diagnosis of ischemic bowel in a diabetic patient with no abdominal pain. Another example is a patient with a language barrier who is not able to describe his or her symptoms clearly, leading the clinician to misinterpret the history. Patient nonadherence to recommended care can also be viewed as no-fault, as in the case of a patient diagnosed with colon cancer who did not obtain a recommended screening colonoscopy.⁶ In one study, no-fault errors accounted for 7% of diagnostic errors.⁷

System errors occur as a result of “latent” faults in the process of delivering care and can be technical or organizational in nature.⁶ Examples of diagnostic errors related to technical issues are misdiagnosis or delayed diagnosis resulting from lack of appropriate testing or equipment or from incorrect laboratory results caused by technical problems with equipment. Organizational shortcomings that contribute to diagnostic errors include imperfections in department policies, error tolerance culture, poor patient care coordination, communication problems, inadequate staff training, poor working conditions, unavailability of acute specialty care, and failing to follow up with patients having abnormal diagnostic study results.⁶ Excessive workload and heavy administrative responsibilities also can contribute to clinician decision errors.

An example of a specific clinical organizational system error would be a missed or delayed diagnosis of a cancer on a chest x-ray due to lack of an “over-read” by a radiologist. Due to cost, many private practices do not send all radiographs for a radiologist’s interpretation. Another example is a patient with a severe eye injury who develops complications after being transferred to another hospital because there is not an on-call ophthalmologist at the presenting hospital.⁶ Delays in reviewing patient laboratory results are a significant system-based source of medical errors. In one study, 83% of the physician respondents reported at least one delay in reviewing test results in the past two months, with 18% reporting five or more delays in reviewing test results over the same time period.⁸

Cognitive errors are caused by gaps in knowledge or experience, inadequate interpretation of diagnostic studies, or succumbing to faulty heuristics and biases.⁶ With cognitive errors, incorrect perception or interpretation of a clinical situation results in faulty differential diagnosis development. Confirmation bias is one type of cognitive error—once supporting information is found for a diagnosis, the search for information to rule out the diagnosis stops.⁶

An example of this would be a patient with an ankle fracture who is discharged with a missed proximal fibula fracture after the clinician performs a physical exam only on the ankle and orders an ankle x-ray. A cognitive error like this would occur due to inadvertent omission of an important physical exam component or the clinician not knowing the importance of examining the knee when evaluating an ankle fracture.

It is important to note that clinical decision errors are usually multifactorial. In a study involving 100 cases of diagnostic error in internal medicine, Graber and colleagues determined that in 46% of the cases errors were caused by a combination of system-related and cognitive factors.⁷

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