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	Candidate Evaluation Model	Political Ideology Scaling
Field	Political Psychology	Political Psychology
Family	Latent structure	Latent structure
Year of origin	1995	1985
Originator	Milton Lodge, Marco Steenbergen & Donald Kinder	Keith Poole & Howard Rosenthal
Type	Latent evaluation model	Latent ideal-point model
Seminal source	Lodge, M., Steenbergen, M. R., & Brau, S. (1995). The responsive voter: Campaign information and the dynamics of candidate evaluation. American Political Science Review, 89(2), 309-326.	Poole, K. T., & Rosenthal, H. (1985). A spatial model for legislative roll call analysis. American Journal of Political Science, 29(2), 357-384.
Aliases	Impression-Driven Evaluation Model, Online Processing Model, Candidate Trait Evaluation Model	NOMINATE, Ideal Point Estimation, IRT Ideology Scaling, Spatial Voting Scaling
Related	4	4
Summary	A candidate evaluation model represents how voters form overall assessments of political candidates as a latent function of perceived traits (competence, leadership, integrity, empathy), partisanship, issue proximity, and affect. It spans the trait-based factor models of Kinder et al. (1980) and the online-processing tally model of Lodge, Steenbergen and Brau (1995), which describes evaluation as a running summary updated as information arrives.	Political ideology scaling estimates actors' positions on one or more latent ideological dimensions from their observed choices, most often legislators' roll-call votes, but also survey responses and donations. The dominant methods are Poole and Rosenthal's NOMINATE (1985) and the Bayesian item-response-theory (IRT) approach of Clinton, Jackman and Rivers (2004), which place legislators and the proposals they vote on in a common spatial map.