Person:

Spirling, Arthur

We study the critical opinions of expert movie reviewers as an item response problem. Building on earlier ‘unfolding’ models, we develop a framework that models an individual’s decision to approve or disapprove of an item. Using this approach, we are able to recover the locations of movies and ideal points of critics in the same multi-dimensional space. We demonstrate that a three dimensional model captures much of the variation in critical opinions. The first dimension signifies movie ‘quality’ while the other two connote the nature and sub ject matter of the films. We then demonstrate that the dimensions uncovered from our ‘utility threshold model’ are statistically significant predictors of a movie’s success, and are particularly useful in predicting the success of ‘independent’ films.

We consider and explore structural breaks in a day-by-day time series of civilian casualties for the current Iraq conflict: an undertaking of potential interest to scholars of international relations, comparative politics, and American politics. We re- view Bayesian change-point techniques already used by political methodologists before advocating and briefly describing the use of reversible-jump Markov chain Monte Carlo techniques to solve the estimation problem at hand. We find evidence of four change points, all associated with increasing violence, approximately contemporaneous with some important state building events. We conclude with a discussion of avenues for future research.

Legislative voting records are an important source of information about legislator preferences, intra-party cohesiveness, and the divisiveness of various policy issues. Standard methods of analyzing a legislative voting record tend to have serious drawbacks when applied to legislatures, such as the UK House of Commons, that feature highly disciplined parties, strategic voting, and large amounts of missing data. We present a method (based on a Dirichlet process mixture model) for analyzing such voting records that does not suffer from these same problems. Our method is model-based and thus allows one to make probability statements about quantities of interest. It allows one to estimate the number of voting blocs within a party or any other group of MPs. Finally, it can be used as both a predictive model and an exploratory model. We illustrate these points through an application of the method to the voting records of Labour Party MPs in the 1997-2001 session of the UK House of Commons.

We study the performance of political science journals in terms of their contribution to intellectual exchange in the discipline. Relying on the interplay of citation patterns, our method is simple, cheap, objective and captures the influence of journals in a meaningful way. We find that the American Political Science Review , World Politics and International Organization lead the field. In contrast to previous sub jective studies, we also find that economics is a key influence on political science, much more so than sociology.

Limited dependent variable (LDV) data are common in political science, and political methodologists have given much good advice on dealing with them. We review some methods for LDV "change point problems" and demonstrate the use of Bayesian approaches for count, binary, and duration-type data. Our applications are drawn from American politics, Comparative politics, and International Political Economy. We discuss the tradeoffs both philosophically and computationally. We conclude with possibilities for multiple change point work.