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July • 26 • 2023

The Impact of Cognitive Bias on Diagnostic Error


By Coverys Risk Management 



Everyone is vulnerable to cognitive bias. However, when it affects practitioners’ decisions, it can lead to diagnostic error, harming both the patient and the provider.

Everyone is vulnerable to cognitive bias. Unfortunately, diagnostic errors may occur if unchecked cognitive biases impact our decision-making process. To prevent diagnostic errors, providers must be aware of their cognitive biases and take steps to counteract them.

What Is Cognitive Bias?

Biases can take many different forms. Some are implicit, occurring automatically and unintentionally. Implicit biases may not accurately reflect our beliefs. Others are explicit, involving attitudes of which the individual is aware.

According to the University of Texas at Austin, “Cognitive biases are errors in thinking that affect people’s decision-making in virtually every situation.” We may believe we are acting and thinking rationally and accurately, however, even intelligent and educated individuals make such errors.

In a paper published by the University of Pennsylvania, Richard L. Byyny, MD, FACP, explains that everyone has biases, often due to using mental shortcuts. Even people with good intentions may unknowingly act from unconscious biases, which can lead to unintended and negative consequences. These unconscious biases can be related to a wide range of factors, such as age, race, gender, employment, and education.

Types of Cognitive Biases

According to The Joint Commission, more than 100 cognitive biases have been identified, including:
  • Anchoring – Initial information and impressions become an anchor. People can fail to adjust their impressions despite new information.
  • Ascertainment – Prior expectations shape decision-making. This bias can involve stereotyping.
  • Availability – People judge the likelihood of a diagnosis based on the ease with which they can retrieve examples, favoring more familiar, common, recent, or memorable assumptions.
  • Confirmation – People selectively notice or seek information that confirms existing opinions or impressions.
  • Diagnostic momentum – A diagnosis has been made, and people are less willing to consider alternatives.
  • Framing effect – Decision-making is impacted by the way information is presented, including the source and context.
  • Search satisficing – People stop looking for signals once something has been identified or a diagnosis has been made.

Cognitive Bias Can Lead to Diagnostic Errors

The Joint Commission says cognitive biases have been identified as a contributor in many sentinel events. For example, confirmation biases can contribute to wrong-site surgeries and anchoring bias can contribute to delays in treatment.

Cognitive bias can also be a significant source of diagnostic error. Coverys data shows that diagnosis-related allegations were the most expensive and second-most frequent type of allegations reported between 2018 and 2022. During this five-year period, diagnosis-related allegations accounted for roughly one-fourth of all events and nearly 40% of indemnity paid.

Several factors can lead to allegations of diagnostic error, but clinical decision-making is the most common – accounting for around 60% of all diagnostic-related allegations. This category can be broken down further to show the most common clinical decision-making risk issues:
  • Narrow diagnostic focus.
  • Inadequate or inappropriate testing.
  • Misinterpretation of diagnostic studies.
  • Failure to adequately assess the patient’s condition.
  • Family or personal history.
Coverys data from 2018-2022 shows that over half of closed claims involved allegations of diagnostic error. In these cases, three risk details are particularly significant, accounting for more than two-thirds of all diagnostic-related cases:
  • 36% of cases involved a failure to order or appreciate images or labs.
  • 29% of cases involved a failure to obtain, properly obtain, or appreciate the patient’s history and physical examination.
  • 13% of cases involved a negligent referral or a failure to follow up on a referral.

Errors Can Lead to Second Victim Syndrome

When cognitive biases lead to adverse events, both the patient and provider can suffer.
Second victim syndrome may occur when healthcare professionals become traumatized after an error leads to an adverse event. According to research by Ozeke et al., published in Advances in Medical Education and Practice, second victim syndrome impacts 10.4% to 43.3% of providers after an adverse event. Nearly half of all healthcare providers experience second victim syndrome at some point, but many stay silent due to the absence of an established reporting system and the fear of litigation. However, even if they are silent, the trauma manifests as shame, guilt, anxiety, grief, and depression. Some providers quit practicing medicine as a result.

Many Allegations Come Down to Communication

A breakdown of communication is at the heart of many allegations involving diagnostic error and cognitive bias.
For example, unlicensed personnel who receive critical values may not recognize the significance of these values. If providers don’t receive important results, a failure to follow up may occur. If values are only delivered orally, misinterpretation can occur.

Since communication is at the heart of everything, fixing communication breakdowns is a critical element of addressing cognitive bias and diagnostic error. The Joint Commission suggests the following:
  • Promote collaborative decision-making to help combat assumptions, hasty interpretations, or wrong conclusions.
  • Develop communication standards and processes for initiating dialogue.
  • Take differing communication styles, disparate communication skills, and limited modes of communication into account.

Overcoming Bias

Bias is a natural part of human existence, but providers can take steps to become aware of their biases and lessen the impact on decision-making. Harvard Implicit Association Tests (HIAT) can help providers recognize their biases. Furthermore, providers should reflect on their own reaction to uncertainty and how this reaction may lead to biases. Here are some tips from an article published in the Medical Teacher journal:
  • Understand your gut reaction to uncertainty. People have different reactions to the unknown.
  • Diagnose your uncertainty. Work on identifying the root cause of your reaction to the unknown.
  • Identify cognitive biases. Common patterns that help providers think quickly can also lead to cognitive bias and false assumptions, misdiagnosis, and errors (FAME). Work on recognizing these patterns.
  • Plan for uncertainty. Anticipate failure. Lead with curiosity.

Objective Bias Assessment

Similar to OSHA’s hazard assessment, think about cognitive bias as a personal or situational hazard. If unchecked, cognitive bias may fester at the root of one’s decision-making process. Some of the strategies to combat cognitive bias include:
  • Collect existing information about your implicit bias – take the HIAT et al.
  • Inspect the workplace for situational triggers – lack of staffing, supplies, time, etc., that may lead to availability bias.
  • Identify personal triggers – insomnia, caffeine, etc., that may lead to framing bias.
  • Conduct incident investigations – test results to make informed decisions and combat confirmation bias.
  • Identify hazards associated with emergency and non-routine situations – plan for uncertainty to avoid ascertainment bias.  
  • Characterize the nature of identified bias, identify interim control measures, and prioritize bias control – Will lack of exercise and lack of supplies exasperate your search satisficing bias? Plan accordingly.  
Humans have biases and make mistakes — and healthcare providers are only human. Acknowledging this is a key step toward controlling biases and reducing diagnostic errors.
This presentation is based, in part, on a Coverys presentation “Examining the Relationship Between Diagnostic Error and Cognitive Bias,” presented by Jenelle E. Arnao, DHS, MS, CPHRM.

Copyrighted. No legal or medical advice intended. This post includes general risk management guidelines. Such materials are for informational purposes only and may not reflect the most current legal or medical developments. These informational materials are not intended, and must not be taken, as legal or medical advice on any particular set of facts or circumstances. 



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