Diagnostic Error and Cognitive Bias in Healthcare
Diagnostic errors are among the most common, costly, and dangerous of all medical errors. The National Academy of Medicine (formerly IOM) published "Improving Diagnosis in Health Care" in 2015, highlighting that most people will experience at least one diagnostic error in their lifetime. CPHQ candidates should understand the types of diagnostic errors, contributing factors, and improvement strategies.
Types of Diagnostic Errors
Diagnostic errors can be classified as missed diagnoses (the diagnosis is never made), delayed diagnoses (the correct diagnosis is made but not in a timely manner), and wrong diagnoses (a different condition is diagnosed). These errors can occur at any point in the diagnostic process: during the clinical encounter (history, physical exam), during testing (ordering, performing, or interpreting tests), during follow-up (tracking test results and referrals), or during the integration of information into a coherent clinical picture. Research suggests that diagnostic errors contribute to approximately 10% of patient deaths and account for a significant proportion of malpractice claims.
Cognitive Biases
Cognitive biases are systematic errors in thinking that affect clinical decision-making. Anchoring bias occurs when a clinician locks onto a diagnosis early and fails to adjust despite contradictory evidence. Availability bias leads clinicians to consider diagnoses that come most easily to mind, often based on recent experience. Confirmation bias causes clinicians to seek information that confirms their existing hypothesis while ignoring disconfirming data. Premature closure is the tendency to stop the diagnostic process once a satisfactory diagnosis is reached, without considering alternatives. Framing effect occurs when the way information is presented influences the diagnostic assessment.
System-Level Contributing Factors
Beyond cognitive biases, system-level factors contribute to diagnostic errors. These include inadequate time for clinical encounters, poor communication during handoffs, fragmented care across multiple providers, lack of feedback to clinicians about diagnostic outcomes, electronic health record usability issues, test result tracking failures, and limited access to decision support tools. Addressing diagnostic error requires attention to both cognitive and system-level factors.
Improvement Strategies
Strategies for reducing diagnostic errors include implementing structured diagnostic frameworks (such as differential diagnosis checklists), using clinical decision support tools, establishing reliable test result notification and follow-up systems, encouraging diagnostic time-outs (pausing to reconsider the differential diagnosis), fostering a culture that welcomes diagnostic uncertainty and second opinions, and providing feedback to clinicians about diagnostic outcomes. Calibration training, where clinicians learn about their own cognitive biases, can also improve diagnostic accuracy.
Quality Professional's Role
Quality professionals can support diagnostic safety by tracking diagnostic-related events and near misses, including diagnostic accuracy in case review activities, ensuring that electronic health record systems support the diagnostic process (for example, through reliable results management), advocating for adequate time and resources for clinical encounters, and incorporating diagnostic safety into the organization's patient safety agenda. The Society to Improve Diagnosis in Medicine (SIDM) provides resources and tools for organizations working to reduce diagnostic error.