The Effect of Billboards on Turnout in 4 States: A Randomized Experiment

This paper presents the design and results of a voter mobilization field-experiment conducted during the 2019 election in conjunction with Vote.org. To test the effect of non-partisan voter mobilization billboards fitted with Election Day information, maps of study areas in four states were overlaid with a grid (or “fishnet”) containing 3-mile by 3-mile cells. Cells were randomly selected to be in the treatment or control group. All available billboards in the treatment cells that met certain criteria were purchased and fitted with a reminder to vote. Across the four states, 207 billboards were treated and 142 served as control billboards for the weeks leading up to Election Day. Results indicated that registered voters living in treated cells had a probability of voting that was higher than those living in control cells. The effect size was similar in magnitude to comparable mobilization treatments and was strongest among mid-propensity voters.