Do Primaries Improve Evaluations of Public Officials? Experimental Evidence from Mexico

Do nomination rules shape how voters evaluate their representatives? Some scholars argue that, in places where trust in political parties is low, primary elections can be an electoral asset by improving how politicians are regarded by voters. Yet, this claim has received little empirical scrutiny. A survey experiment in Mexico, where parties have employed several nomination rules in recent years, allows us to assess this argument. We find that, by and large, providing information about the method by which a politician was nominated to office—relative to not providing such information—has virtually no impact on how voters evaluate the politician. At the same time, we uncover evidence of a relative advantage of primary elections over more centralized nomination rules. Specifically, learning that a politician was nominated in a primary election—relative to learning that they were appointed by party elites—improves voter perceptions of politician quality and increases their reported willingness to vote for the politician in the future. Our results have important implications for political parties in many developing countries and new democracies, where intraparty democracy is increasingly popular.