Ideal and Real Party Positions in the 2015–2016 Spanish General Elections

Abstract

In this paper, using data from the pre-electoral and post-electoral Spanish surveys conducted by the Centro de Investigaciones Sociologicas (CIS) in the 2015 and 2016 general elections and assuming that parties maximize votes, we use an iterative algorithm to derive the optimal party positions (as predicted by spatial competition models based on proximity and directional models of voting). These optimal policy positions constitute a Nash equilibria, in which no party can increase its vote share by changing unilaterally its policy position. Then we compare the actual ideological positions of Spanish parties (as perceived by all voters) to their ideological party positions. Our aims are to examine the predictive power of proximity and directional models in the two Spanish electoral processes, to explore the degree to which parties deviate from their ideal positions and to examine the evolution of party positions from December 2015 to June 2016.