In Ideology and Congress, authors Poole and Rosenthal have analyzed over 13 million individual roll call votes spanning the two centuries since Congress began recording votes in 1789. By tracing the voting patterns of Congress throughout the country's history, the authors find that, despite a wide array of issues facing legislators, over 81 percent of their voting decisions can be attributed to a consistent ideological position ranging from ultraconservatism to ultraliberalism. In their classic 1997 volume, Congress: A Political Economic History of Roll Call Voting, roll call...

This book presents a geometric voting model for analyzing 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. These maps can be used to study a wide variety of topics related to...

This book presents a geometric voting model for analyzing 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. These maps can be used to study a wide variety of topics related to...