Professions play a key role in determining the division of labor and the returns to skilled work. This paper studies the productivity difference between physicians and nurse practitioners (NPs), two health care professions performing overlapping tasks but with stark differences in background,...

We develop a model of the efficiency of medical testing based on the frequency of negative CT scans for pulmonary embolism. The model is estimated using a 20% sample of Medicare claims from 2000-2009. We document enormous heterogeneity in testing conditional on patient population. Less...