Which doctor? Combining vignettes and item response to measure clinical competence

We develop a method in which vignettes-a battery of questions for hypothetical cases-are evaluated with item response theory to measure the clinical competence of doctors. The method, which allows us to simultaneously estimate competence and validate the test instrument, is applied to a sample of medical practitioners in Delhi, India. The method gives plausible results, rationalizes different perceptions of competence in the public and private sectors and pinpoints several serious problems with health care delivery in urban India. The findings confirm, for instance, that the competence of private providers located in poorer areas of the city is significantly lower than those in richer neighborhoods. Surprisingly, similar results hold for providers in the public sector with important implications for inequalities in the availability of health care.