Vincent Pons (2016). Will a Five-Minute Discussion Change Your Mind? A Countrywide Experiment on Voter Choice in France. Harvard Business School Working Paper, No. 16-079, January 2016.
In a massive study involving over 5 million households, canvassing 15% of the households in a region resulted in a 1.8% to 2% increase in candidate vote share.
Existing evidence on the impact of door-to-door canvassing comes from small-scale experiments that assign treatment at the individual level (at which voter choices are difficult to measure) and assume greater control over canvassers’ selection and behavior than is typical to most campaigns. This paper takes a different approach by assigning entire precincts to either a control group or a treatment group in a countrywide experiment during François Hollande’s campaign in the 2012 French presidential elections. Overall, activists supporting the Parti Socialiste’s candidate knocked on five million doors. Visits did not affect voter turnout but increased Hollande’s vote share in the first round at the expense of his right-wing opponents and accounted for one fifth of his victory margin in the second round. This impact largely persisted in later elections, suggesting that even brief one-on-one discussions can have a large and lasting persuasion effect.