Estimating Spatial Preferences from Votes and Text

TitleEstimating Spatial Preferences from Votes and Text
Publication TypeJournal Article
Year of Publication2018
AuthorsKim ISong, Londregan J, Ratkovic M
JournalPolitical Analysis
Keywordsdiscrete choice models, multidimensional scaling, spatial voting model, statistical analysis of texts
AbstractWe introduce a model that extends the standard vote choice model to encompass text. In our model, votes and speech are generated from a common set of underlying preference parameters. We estimate the parameters with a sparse Gaussian copula factor model that estimates the number of latent dimensions, is robust to outliers, and accounts for zero inflation in the data. To illustrate its workings, we apply our estimator to roll call votes and floor speech from recent sessions of the US Senate. We uncover two stable dimensions: one ideological and the other reflecting to Senators' leadership roles. We then show how the method can leverage common speech in order to impute missing data, recovering reliable preference estimates for rank-and-file Senators given only leadership votes.