Does Full Insurance Increase the Demand for Health Care?

We estimate the causal impact of having full health insurance on healthcare expenditures. We take advantage of a unique quasi-experimental setup in which deductibles and co-payments were zero in a managed care plan and nonzero in regular insurance, until a policy change forced all individuals with an active plan to cover a minimum amount of their expenses. Using panel data and a nonlinear difference-in-differences strategy, we find a demand elasticity of about -0.14 comparing full insurance with the cost-sharing model and a significant upward shift in the likelihood to generate costs.