ABSTRACT
Throughout this book we describe the policy positions of political actors in terms of a set of distinct “dimensions,” each taken to capture a substantively important feature of the potential for political disagreement. Taken together, these dimensions combine to span a multidimensional common policy “space” in which both the policy positions of politicians and the ideal points of citizens can be located, according to their substantive positions on each dimension. In previous chapters we discussed how to measure positions on a given dimension. We now turn to the problem of characterizing the common policy space in each country, taking all important dimensions together. In order to do this, we must answer three questions.
