The role of the political context in voting indecision

• We examine how context affects voters' likelihood of revealing their vote intention.
• Close elections are associated with higher levels of undecided voters.
• The number of parties is associated with higher levels of undecided voters.
• Incumbent’s supporters become more undecided when governments are unpopular.

A substantive portion of the electorate declares in pre-electoral surveys that they are undecided. However, little has been done in trying to understand who these voters are and how they finally decide their vote. In this article, we try to advance the literature by disentangling the circumstances under which voters are more likely to be undecided. While the traditional approach to the study of electoral indecision has been to characterize which individual traits make voters more likely to be undecided, this article provides consistent evidence showing that key elements of the political context may also affect electoral indecision. Using long-term harmonized data from Spanish pre-electoral surveys over 30 years, we find that voting indecision is influenced by two different types of contextual factors. First, there are some political contexts that reduce voters' cognitive costs when deciding their vote, i.e. the level of electoral competitiveness and the number of parties competing in the elections. Second, there are other political contexts that increase voters' social or expressive costs, i.e. the level of government popularity, since costs of expressing preference for the party in government increases when its public image is undermined.