Linking Theory and Empirics: Testing Spatial Voting Theory

Abstract

No matter how elegant or aesthetically pleasing, a model of politics must ultimately be tested against the real world. Otherwise, it remains, at best, an interesting set of abstractions. (Enelow and Hinich 1984, 169) One of the main virtues of spatial voting theory is its high degree of both parsimony and precision relative to other theories of voting behavior. Spatial theory posits that a voter's ideological proximity to candidate positions is the sole (or at least the central) determinant of vote choice. Furthermore, most accounts of spatial voting assume a specific, often formally stated relationship between ideology and voting behavior. The clear and rigorous statement of theoretical axioms in the spatial voting framework generally yields strong and specific empirical predictions. Therefore, spatial theory presents more robust opportunities for falsification than do most other approaches to the study of voting as well as most political science theories more generally. To the extent that spatial voting survives these opportunities for falsification, the theory should be viewed as more promising. Although spatial theory generates clear, testable hypotheses, obtaining the measurements necessary for testing these hypotheses – specifically estimates of the ideology of voters and the positions taken by candidates – generally has not been possible with existing measurement techniques. Previous work attempting to test the empirical implications of spatial voting models has relied on heroic assumptions or rough proxies in order to obtain estimates of the ideology of voters and candidates on the same scale.