Estimates of the Spatial Voting Model

In this chapter, the authors survey the empirical success of the spatial (or geometric) theory of voting. Empirical work lagged behind the development of theory until about 30 years ago and since then has exploded, with ideal-point estimation emerging as an important methodological subfield in political science. Empirical applications of spatial theory are now legion, and the basic news is that the spatial model has been enormously successful in explaining observed political choices and outcomes at both the elite and mass levels. In the United States, empirical estimates of the spatial model also help to explain incongruities between the median voter theorem and party polarization. These empirical estimates have demonstrated that the theory is extremely powerful on a number of levels—indeed, that it is one of the most successful mathematical theories in the social sciences.