Bandwagon Voter

The bandwagon voter is a staple concept in electoral behavior research, describing individuals whose choices are shaped less by ideology, policy alignment, or partisan loyalty than by the desire to back a winner. The underlying bandwagon effect was formalized by economist Harvey Leibenstein in a 1950 Quarterly Journal of Economics article on consumer demand, and was extended to elections by political scientists studying how poll coverage influences vote choice.

Bandwagon voters typically respond to cues such as published opinion polls, prediction markets, endorsement cascades, primary results, and media narratives about "momentum." The psychological mechanisms most often cited include social conformity, the wish to feel part of a winning coalition, low information costs (a frontrunner signals viability), and expressive utility from supporting the eventual victor.

Empirically, the effect is contested. Studies of the 1980 and 1992 U.S. presidential elections, the 1997 UK general election, and various German Bundestag races have found modest but measurable shifts toward perceived frontrunners after favorable polling. Other work — notably research on the underdog effect — finds the opposite pattern among some voter segments who rally to trailing candidates. The size of any bandwagon effect tends to depend on:

• Salience and frequency of horse-race coverage
• Strength of prior partisan attachment (weaker partisans bandwagon more)
• Closeness of the race
• Whether the system is plurality or proportional, since strategic incentives differ

The concept is closely related to, but distinct from, strategic voting (where the motive is to avoid wasting a vote) and social desirability bias in polling. Several democracies — including France, Italy, and Singapore — restrict the publication of polls in the days immediately before an election partly out of concern about bandwagon dynamics. The European Commission and academic bodies such as the World Association for Public Opinion Research have periodically reviewed the empirical basis for such blackout laws, generally finding mixed evidence.