Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
We find that Ohio’s “Vax-a-Million” lottery increased first-dose COVID-19 vaccinations by between 50,000 and 100,000, with most of the additional doses occurring during the two weeks between the announcement and the first lottery drawing. We use county-level data and two empirical approaches to provide causal estimates of the lottery in Ohio. First, a difference-in-differences design compares vaccination rates in border counties in Ohio and Indiana before and after the announcement. Second, we use a pooled synthetic control method to construct a counterfactual for each of Ohio’s counties using control counties in Indiana, Michigan, and Pennsylvania. The synthetic control analysis reveals larger increases in vaccination rates in more populous counties. Our estimates imply that Ohio paid about $75 per additional starting dose during this period.