Repeated treatment in a GOTV field experiment: Distinguishing between intensive and extensive margin effects

Technological advancements and the increasingly large amounts spent for elections have made it easier for get-out-the-vote (GOTV) campaigns to contact potential voters many times prior to elections. However, the effects of repeated exposure to GOTV treatment have received little attention in the academic literature. Multiple treatments can increase the intensive margin of treatment—by increasing the number of times that treated individuals are exposed to the treatment—or the extensive margin of treatment—by increasing the number of people who are exposed to at least one treatment attempt. We analyze the differences between a treatment with one automated GOTV call and a treatment with three GOTV calls to isolate the effect of changes in the extensive and intensive margins of treatment on voting rates. On the intensive margin, we find that answering one additional call is associated with an approximately 0.6% point increased probability to vote. On the extensive margin, we find that answering one additional call is associated with an approximately one percentage point increased probability to vote. This evidence is consistent with the academic literature on commercial advertising, which finds that repeated exposures to commercial advertisements have diminishing marginal effects.