He practices general internal medicine and directs the Center for Value-Based Care Research. His research examines quality of care and decision making for common medical conditions, with an emphasis on tailoring treatment to patients based on individual risk and preferences. His methods include large observational studies, risk modeling and cost-effectiveness analysis. His areas of interest include pneumonia and influenza, venous thromboembolism, coronary artery disease and public reporting of healthcare quality. The goal of his research is to help physicians and patients make better healthcare decisions in order to improve outcomes and control costs.