BIASES AND HEURISTICS IN MEDICAL DECISION-MAKING: A REVIEW OF THE LITERATURE AND STUDY METHODOLOGIES

Purpose: This study reviews the medical decision making literature for claims made about cognitive biases and heuristics in decision-making with an eye to whether the claim is made about decisional biases in patients vs. clinicians, whether the study was based on hypothetical decision-making (survey) vs. actual decision making, and if hypothetical, whether the decision makers studied were representative of the population actually making such a decision (e.g., patients or clinicians) or not (e.g. undergraduate college students).  We also reviewed whether hypothetical decision scenarios gave any information about cost or patient preferences, values, or goals. 

Method: Using the search terms "heuristic," "cognitive bias," "decision making," we identified and screened 2,459 titles, yielding 260 articles, and extracted data from 129.  Inclusion criteria were empirical studies about biases in medical decision-making (treatment or diagnosis) from 1990-present. 

Results: 46% of the studies studied cognitive biases in medical personnel’s decision-making and 59% studied cognitive biases in patients’ decision making.  81% of the studies were based on hypothetical decisional scenarios as opposed to actual decision-making.  For the studies on cognitive biases in patients, 72% of the studies were representative of the population actually making such a decision, but 34% were not (e.g., were undergraduate college students).  Only 19% of the hypothetical decisional scenarios asking clinicians to make a treatment recommendation included any information about patient preferences, values, or goals.  Only 22% of the hypothetical decisional scenarios asking patients or clinicians to make treatment decisions included any information about cost. For a list of cognitive biases studied see Figure 1. 

Conclusions: Claims about cognitive biases and heuristics in medical decision making should be tempered by the fact that most studies (81%) are not based on actual decision-making but on hypothetical decision making and by the fact that 34% are based on decision-making in populations unlikely to be making that medical decision (e.g., undergraduates).

Figure 1 - Cognitive Biases and Heuristics in Medical Decision Making Ambiguity Aversion Anchoring Availability bias Confirmation Bias Decoy Effect Frequency Bias Hyperbolic Discontinuity Impact Bias/ Affective Forcasting Bias Loss Aversion Bias Omission/Commission Bias Optimism/Overconfidence Bias Outcome Bias Recency/Primacy Bias Relative Risk Bias Representativeness Bias Risk Assessment Bias Sunk Cost Bias