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	Ordinal Exploratory Factor Analysis	Item Response Theory (IRT)
Ämnesområde	Psykometri	Psykometri
Familj	Latent structure	Latent structure
Ursprungsår	1978–1984	1952–1968
Upphovsperson	Bengt Muthén	Frederic M. Lord (and Allan Birnbaum for the 2PL/3PL models)
Typ	Latent variable / dimension reduction	Probabilistic measurement model
Ursprungskälla	Flora, D. B. & Curran, P. J. (2004). An empirical evaluation of alternative methods of estimation for confirmatory factor analysis with ordinal data. Psychological Methods, 9(4), 466–491.	Lord, F. M. & Novick, M. R. (1968). Statistical Theories of Mental Test Scores. Addison-Wesley.
Alias	ordinal factor analysis, polychoric EFA, categorical EFA, EFA for ordinal data	IRT, latent trait theory, item characteristic curve theory, modern test theory
Närliggande	5	5
Sammanfattning	Ordinal exploratory factor analysis discovers latent factors underlying a set of ordinal items — typically Likert scales — by computing polychoric correlations among the items and then applying a weighted least squares estimator. It avoids the distortions that arise when continuous EFA methods are naively applied to ordered categorical responses.	Item response theory models the probability that a respondent answers an item correctly (or endorses it) as a function of the respondent's latent trait level and the item's own statistical properties — difficulty, discrimination, and guessing. Unlike classical test theory, IRT places persons and items on the same scale, yielding measurement that is sample-independent for items and test-independent for persons.