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	Political Ideology Scaling	Political Ideology Scale
Field	Political Psychology	Political Psychology
Family	Latent structure	Process / pipeline
Year of origin	1985	1990
Originator	Keith Poole & Howard Rosenthal	Hans-Dieter Klingemann & Norberto Bobbio
Type	Latent ideal-point model	Self-report
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.	Fuchs, D., & Klingemann, H. D. (1990). The left-right schema. In M. Kent Jennings & Jan W. Van Deth (Eds.), Continuities in political action. Berlin: De Gruyter.
Aliases	NOMINATE, Ideal Point Estimation, IRT Ideology Scaling, Spatial Voting Scaling	Left-Right Scale, Ideology Continuum, Political Spectrum Scale
Related	4	3
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.	The Political Ideology Scale measures individual self-placement on a left-right political spectrum, capturing fundamental preferences for government role, economic organization, and social values. The single-item self-placement measure (most common) asks respondents to rate themselves on a 0-10 or 0-100 continuum; multi-item versions assess distinct ideological dimensions (economic policy, social policy, nationalism). The left-right axis remains the dominant organizing principle of political competition globally, predicting party choice, policy preferences, and electoral behavior despite critiques that it oversimplifies multidimensional political space.