Compare methods

	Political Ideology Scaling	Ideological Constraint Analysis
Field	Political Psychology	Political Psychology
Family	Latent structure	Latent structure
Year of origin	1985	1964
Originator	Keith Poole & Howard Rosenthal	Philip E. Converse
Type	Latent ideal-point model	Belief-system structure analysis
Seminal source	Poole, K. T., & Rosenthal, H. (1985). A spatial model for legislative roll call analysis. American Journal of Political Science, 29(2), 357-384.	Converse, P. E. (1964). The nature of belief systems in mass publics. In D. E. Apter (Ed.), Ideology and Discontent (pp. 206-261). New York: Free Press. ISBN: 9780029006702
Aliases	NOMINATE, Ideal Point Estimation, IRT Ideology Scaling, Spatial Voting Scaling	Belief System Constraint, Attitude Constraint Analysis, Issue Consistency Analysis
Related	4	4
Summary	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.	Ideological constraint analysis measures the degree to which an individual's or a public's political attitudes hang together in a coherent, predictable structure, the extent to which knowing a person's position on one issue lets you predict their positions on others. Introduced by Converse (1964) as the defining feature of a belief system, it is assessed through inter-item correlations, factor/latent-dimension models, and constraint indices.