Arrow (1963) hypothesized that demand-side moral hazard induced by health insurance leads to supply-side expansions in healthcare markets. Capturing these effects empirically has been challenging, as non-marginal insurance expansions are rare and detailed data on healthcare labor and capital is...

We study over 20 million emergency room (ER) discharges in Massachusetts and three comparison states to estimate the impact of Massachusetts health care reform on claims for Workers' Compensation (WC). Prior evidence on the relationship between health insurance and WC claiming behavior is mixed....