In government-sponsored health insurance, subsidy design affects market outcomes. First, holding premiums fixed, subsidies determine insurance uptake and average cost. Insurers then respond to these changes, adjusting premiums. Combining data from the first four years of the California ACA...

Who bears the consequences of administrative problems in healthcare? We use data on repeated interactions between a large sample of U.S. physicians and many different insurers to document the complexity of healthcare billing, and estimate its economic costs for doctors and consequences for...