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 percent overall, with the effects concentrated in men (18 percent increase) and in residents of democratic counties (10 percent increase); there is suggestive evidence that the increase in voting reflected new voter registrations, rather than increased turnout among preexisting registrants. There is no evidence of an increase in voter turnout in subsequent elections, up to and including the November 2010 midterm election.