Does Microtargeting Work? Evidence from an Experiment During the 2020 United States Presidential Election

This event is Hybrid. Individuals interested in attending can do so in-person by coming to Nuffield College or via Zoom by requesting a link to the talk via our website.

Political science research consistently shows that political advertisements have small and uniform effects. This contrasts with claims that microtargeted campaigning can sway electoral outcomes and poses a threat to society. This paper introduces a novel experimental design simulating a targeted campaign to empirically test whether targeting political advertisements can be effective. Participants in an online survey experiment view one of five anti-Biden advertisements. Respondents assigned to control are allocated advertisements at random. This data is used to train a model predicting Biden favorability from advertisement and pre-treatment traits. Respondents in the treatment group view the advertisement that this model predicts to be the most effective. The difference between targeted and random allocation is an 8.7 percentage point increase in Biden dislike and a 7.1 percentage point decrease in intent to vote Biden among unaligned voters who had not yet cast their vote (N=586). The effect is negligible among partisan voters.