1

Paper

A Note Relating Ideal Point Estimates to the Spatial Model Clinton, Joshua Meirowitz, Adam Uploaded 07-18-2000 Keywords ideal points preference estimation NOMINATE spatial model Abstract Existing preference estimators do not incorporate the full structure of the spatial model. Specifically, they fail to use the sequential nature of the agenda by not constraining the nay location of a bill to be the yea location of the last successful policy. The consequences of this omission may be far-reaching. Not only is information useful for the identification of the model neglected, but more seriously, the dimensionality of the policy space may be incorrectly estimated. Preference and bill location estimates are uninterpretable in terms of the spatial model. We show that under very general assumptions, ML estimates of ideal points that do not constrain the nay locations will differ from ML estimates that constrain the nay locatios -- a difference that does not vanish as the numbers of votes goes to infinity. Additionally, unconstrained models underestimate the true dimensionality of the policy space. We derive a Maximum Likelihood estimator of legislative preferences and bill locations that shares basic assumptions with the spatial model of voting.

2

Paper

Evaluating Measures of Ideology Bishin, Benjamin G. King, Gary Zeng, Langche Uploaded 08-24-1997 Keywords FILTER ADA NOMINATE ideology Abstract A vigorous debate has arisen over the metric used to measure ideology (Jackson and Kingdon 1992, Poole and Rosenthal 1985, Snyder 1991, Krehbiel 1993). Ideology is difficult to measure because legislator's statements may be politically motivated and insincere. This paper evaluates the accuracy of NOMINATE and ADA scores by comparing them to an independent measure, based on background characteristics, developed herein. By Forecasting the Ideology of Legislators Through Elite Response (FILTER), this measure avoids the problems inherent in use of the roll call vote metric. In addition, the FILTER methodology is generalizable to studies of other deliberative bodies. The results show that FILTER scores are highly correlated with NOMINATE and ADA scores.

3

Paper

The Spatial Theory of Voting and the Presidential Election of 1824 Jenkins, Jeffery A. Sala, Brian R. Uploaded 08-15-1997 Keywords spatial voting theory ideological voting presidential selection Nominate scores Abstract One recent analysis claims that in at least five p residential contests since the end of World War II a relatively minor vote shift in a small number of states would have produced Electoral College deadlock, leading to a House election for president (Longley and Peirce 1996). A presidential contest in the House would raise fundamental questions from agency theory - do members "shirk" the collective preferences of their constituent-principals on highly salient votes and, if so, what explains the choices they do make? Can vote choices be rationalized in a theory of ideological voting, or are legislators highly susceptible to interest-group pressures and enticements? We apply a spatial-theoretic model of voting to the House balloting for president in 1825 in order to test competing hypotheses about how MCs would likely vote in a presidential ballot. We find that a sincere voting model based on ideal points for MCs and candidates derived from Nominate scores closely matches the choices made by MCs in 1825.