Voters have different mechanisms to choose among parties, such as personalistic, retrospective or programmatic voting. Within the last, the most prominent device they use to make sense of politics arguably is the left-right scheme. But an important underlying assumption for that is that parties conform to this unidimensional conception of politics. Empirically however, the way parties differentiate varies in dimensionality. What happens if the issues that parties compete over correlate in higher order? Several accounts suggest that it is doubtful whether voters engage in decision environments that complex. This paper engages this puzzle by directly modeling how voters aggregate issues into party rankings. Assuming that voters ‘switch’ heuristics if these rankings do not provide a sufficiently strong signal, it develops hypotheses on how greater issue diversity in party competition influences voter heuristic use. These hypotheses shall be tested in a cross-nationally comparative analysis combining survey with manifesto data.
