The role of partisan cues in voter mobilization campaigns:evidence from a randomized field experiment

The transmission of partisan appeals during election campaigns is widely believed to aid the formation of citizens' candidate preferences, or to serve as rallying cries, thereby increasing turnout. While laboratory and survey experiments show that partisan cues help citizens decide between candidates, and partisan elections see higher turnout than non-partisan elections, it is unclear if party labels and partisan rhetoric cause voters to turn out in higher numbers in real-world elections. We exploit a low-information election in the UK to randomly assign whether campaign phone messages include strong partisan cues or promote the same candidate without such cues. Whereas we find no significant difference in the overall effectiveness of messages with and without partisan cues at increasing turnout, the effectiveness of the former is moderated by party preference: Consistent with the use of acceptance-rejection heuristics, campaign calls with partisan cues are more likely to mobilize party supporters than rival partisans.