Testing the Persuasive Effects of Digital Media : A Cluster Randomized Field Experiment

Although digital advertising is a rapidly growing form of political communication, the effectiveness of digital ad campaigns remains largely unknown. We present results from a randomized experiment in which online campaign ads targeted randomly selected small cities in the context of a Texas Republican primary campaign for lieutenant governor. Results suggest that digital advertising had weak positive effects that fall short of conventional levels of statistical significance. This study may be viewed as a pilot study whose design provides guidance to researchers seeking to conduct more powerful tests of ad effectiveness