The Impact of Medicaid Expansion on Voter Participation: Evidence from the Oregon Health Insurance Experiment

In 2008, a group of uninsured low-income adults in Oregon was selected by lottery for the chance to apply for Medicaid. Using this randomized design and state administrative data on voter behavior, we analyze how a Medicaid expansion affected voter turnout and registration. We find that Medicaid increased voter turnout in the November 2008 Presidential election by about 7% overall, with the effects concentrated in men (18% increase) and in residents of Democratic counties (10% increase); there is suggestive evidence that the increase in voting reflected new voter registrations, rather than increased turnout among pre-existing registrants. There is no evidence of an increase in voter turnout in subsequent elections, up to and including the November 2010 midterm election.