One natural question is: How much of these gains in coverage came from the ACA? Could the higher number of insured people have come from other factors, notably a better economy?
In a recently released National Bureau of Economic Research working paper, we use data from the American Community Survey (ACS) to answer this question. We find that the ACA led to a 5.9 percentage point gain in insurance coverage in Medicaid expansion states and a 3.0 percentage point gain in coverage in nonexpansion states.
