*Swing Blue Alliance conducted a randomized controlled trial of handwritten GOTV cards for the 2023 Ohio Special Election. The postcards encouraged people to vote against a ballot initiative that would have increased the threshold needed to pass Constitutional Amendments from 50% to 60%. The initiative failed to pass. The postcards increased the likelihood of voting by 1.2% (p = 0.079, 90% confidence interval 0.0007508-0.022591). The targets were likely Democrats who had taken a Democratic Primary ballot in one of the last 4 primary elections, and who were unlikely to be reached by phone or canvassing. The treatment group consisted of 38,654 registered voters while 3,684 registered voters were held as controls.
(Duffy, Loewenstein, Newby and Salkever, 2024) (Loewenstein, 2024)