The effect of increased cost-sharing on low-value service use.

We examine the effect of a value-based insurance design (VBID) program implemented at a large public employer in the state of Oregon. The program substantially increased cost-sharing for several healthcare services likely to be of low value for most patients: diagnostic services (e.g., imaging services) and surgeries (e.g., spinal surgeries for pain). Using a difference-in-differences design coupled with granular, administrative health insurance claims data over the period 2008-2012, we estimate the change in low-value service use among beneficiaries before and after program implementation relative to a comparison group not exposed to the VBID. Our findings suggest that the VBID significantly reduced the use of targeted services, with an implied elasticity of demand of -0.22. We find no evidence that the VBID led to substitution to non-targeted services or increased overall healthcare costs. However, we also observe no evidence that the program led to cost-savings.