Browsing by Author "Poole, Keith T."
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Item Recovering a Basic Space from Issue Scales in R(Foundation for Open Access Statistics, 2016) Poole, Keith T.; Lewis, Jeffrey B.; Rosenthal, Howard; Lo, James; Carroll, Roycebasicspace is an R package that conducts Aldrich-McKelvey and Blackbox scaling to recover estimates of the underlying latent dimensions of issue scale data. We illustrate several applications of the package to survey data commonly used in the social sciences. Monte Carlo tests demonstrate that the procedure can recover latent dimensions and reproduce the matrix of responses at moderate levels of error and missing data.Item The Structure of Utility in Spatial Models of Voting(John Wiley & Sons, Inc., 2013) Carroll, Royce; Lewis, Jeffrey B.; Lo, James; Poole, Keith T.; Rosenthal, HowardEmpirical models of spatial voting allow legislators' locations in a policy or ideological space to be inferred from their roll-call votes. These are typically random utility models where the features of the utility functions other than the ideal points are assumed rather than estimated. In this article, we first consider a model in which legislators' utility functions are allowed to be a mixture of the two most commonly assumed utility functions: the quadratic function and the Gaussian function assumed by NOMINATE. Across many roll-call data sets, we find that legislatorsメ utility functions are estimated to be very nearly Gaussian. We then relax the usual assumption that each legislator is equally sensitive to policy change and find that extreme legislators are generally more sensitive to policy change than their more centrally located counterparts. This result suggests that extremists are more ideologically rigid while moderates are more likely to consider influences that arise outside liberal-conservative conflict.