Published online by Cambridge University Press: 19 August 2020
Despite the rapid growth of online political advertising, the vast majority of scholarship on political advertising relies exclusively on evidence from candidates’ television advertisements. The relatively low cost of creating and deploying online advertisements and the ability to target online advertisements more precisely may broaden the set of candidates who advertise and allow candidates to craft messages to more narrow audiences than on television. Drawing on data from the newly released Facebook Ad Library API and television data from the Wesleyan Media Project, we find that a much broader set of candidates advertises on Facebook than television, particularly in down-ballot races. We then examine within-candidate variation in the strategic use and content of advertising on television relative to Facebook for all federal, statewide, and state legislative candidates in the 2018 election. Among candidates who use both advertising media, Facebook advertising occurs earlier in the campaign, is less negative, less issue focused, and more partisan than television advertising.
Except where noted in the text, analyses presented were preregistered (https://osf.io/3px5b) prior to the release of the Facebook Ad Library. We are grateful to Laura Baum, Dolly Haddad, Colleen Bogucki, Mason Jiang, and the numerous undergraduates across our institutions for their efforts on this project. We thank Amanda Wintersieck, Devra Moehler, Abby Wood, and seminar participants at APSA, the Princeton CSDP American Politics seminar, the University of Maryland, the University of Wisconsin, the Wesleyan Media Project 2018 Post-Election Conference, and Yale for comments on previous versions. The Wesleyan Media Project acknowledges funding from the John S. and James L. Knight Foundation and Wesleyan University for 2018. All views and errors are our own. Replication files are available at the American Political Science Review Dataverse at: https://doi.org/10.7910/DVN/IR9XGC