David Chan, Stanford University
"Selection with Variation in Diagnostic Skill: Evidence from Radiologists."
Physicians, judges, teachers, and agents in many other settings differ systematically in the decisions they make when faced with similar cases. Standard approaches to interpreting and exploiting such differences assume they arise solely from variation in preferences. We develop an alternative framework that allows variation in both preferences and diagnostic skill, and show that both dimensions are identified in standard settings under random assignment. We apply this framework to study pneumonia diagnoses by radiologists. Diagnosis rates vary widely among radiologists, and descriptive evidence suggests that a large component of this variation is due to differences in diagnostic skill. Our estimated model suggests that radiologists view false negatives as more costly than false positives, and that this leads less skilled radiologists to optimally choose lower diagnosis thresholds. Variation in accuracy can explain 62 percent of variation in diagnostic decisions, and policies that improve skills perform better than uniform decision guidelines. Misinterpreting skill variation as preference variation can lead to highly misleading results.
David Chan, MD, PhD, is an Assistant Professor of Medicine at the Stanford School of Medicine, an investigator at the Department of Veterans Affairs, and a Faculty Research Fellow at the National Bureau of Economic Research. Drawing on labor and organizational economics, he is interested in studying how information is used in health care, how this affects productivity, and implications for design. He is the recipient of the 2014 NIH Director’s High-Risk, High-Reward Early Independence Award to study the optimal balance of information in health information technology for patient care.
Dr. Chan received master’s degrees in policy and economics from the London School of Economics and Oxford University, where he studied as a Marshall scholar. He holds a medical degree from UCLA and a PhD in economics from MIT. He trained in internal medicine at Brigham and Women’s Hospital and was an instructor of medicine at Harvard Medical School, prior to coming to Palo Alto, where he currently is a hospitalist at the Department of Veterans Affairs, Palo Alto.