Scalingmethods to evaluate the latent dimensions of political behavior and choice have had a substantial impact on our understanding of the properties of legislative roll-call voting. As interest in spatial models of legislatures has grown, these methods have been employed to operationalize theories of the role of preferences and ideology in legislative politics. Scaling procedures and ideal point estimation have enabled the evaluation of the spatial properties of voting and numerous empirical investigations of spatial theories of politics. With the advent of new techniques and more computational power, such methods have become even more widespread in comparative politics. We provide an overview of these methods and applications with a discussion of several challenges and recent developments in the field.