The Influence of the Availability Heuristic on Physicians in the Emergency Department

Heuristics, or rules of thumb, are hypothesized to influence the care physicians deliver. One such heuristic is the availability heuristic, under which assessments of an event's likelihood are affected by how easily the event comes to mind. We examined whether the availability heuristic influences physician testing in a common, high-risk clinical scenario: assessing patients with shortness of breath for the risk of pulmonary embolism.

We performed an event study from 2011 to 2018 of emergency physicians caring for patients presenting with shortness of breath to 104 Veterans Affairs (VA) hospitals. Our measures were physician rates of pulmonary embolism testing (D-dimer and/or computed tomography scan) for subsequent patients after having a patient visit with a pulmonary embolism discharge diagnosis, hypothesizing that physician rates of pulmonary embolism testing would increase after having a recent patient visit with a pulmonary embolism diagnosis due to the availability heuristic.

The sample included 7,370 emergency physicians who had 416,720 patient visits for shortness of breath. The mean rate of pulmonary embolism testing was 9.0%. For physicians who had a recent patient visit with a pulmonary embolism diagnosis, their rate of pulmonary embolism testing for subsequent patients increased by 1.4 percentage points (95% confidence interval 0.42 to 2.34) in the 10 days after, which is approximately 15% relative to the mean rate of pulmonary embolism testing. We failed to find statistically significant changes in rates of pulmonary embolism testing in the subsequent 50 days following these first 10 days.

After having a recent patient visit with a pulmonary embolism diagnosis, physicians increase their rates of pulmonary embolism testing for subsequent patients, but this increase does not persist. These results provide large-scale evidence that the availability heuristic may play a role in complex testing decisions.