Spatial Models of Parliamentary Voting

This book presents a simple geometric voting model for analyzing parliamentary roll call data.

Keith T. Poole (Author)

9780521617475, Cambridge University Press

Paperback, published 11 April 2005

248 pages, 62 b/w illus. 8 tables
22.8 x 15.2 x 1.9 cm, 0.337 kg

'This book achieves its aim of explaining how to build a spatial model and will be essential reading for those engaged in that, while still being readable and related well to real politics.' Political Studies Review

This book presents a simple geometric model of voting as a tool to analyze parliamentary roll call data. Each legislator is represented by one point and each roll call is represented by two points that correspond to the policy consequences of voting Yea or Nay. On every roll call each legislator votes for the closer outcome point, at least probabilistically. These points form a spatial map that summarizes the roll calls. In this sense a spatial map is much like a road map because it visually depicts the political world of a legislature. The closeness of two legislators on the map shows how similar their voting records are, and the distribution of legislators shows what the dimensions are. These maps can be used to study a wide variety of topics including how political parties evolve over time, the existence of sophisticated voting and how an executive influences legislative outcomes.

1. Introduction
2. The geometry of parliamentary roll call voting
3. The optimal classification method
4. Probabilistic spatial models of parliamentary voting
5. Practical issues in computing spatial models of parliamentary voting
6. Conducting natural experiments with role calls
7. Conclusion.

Subject Areas: Political economy [KCP], Politics & government [JP]