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	Analisi di Affidabilità Ordinale	Teoria della risposta all'item (IRT)
Campo	Psicometria	Psicometria
Famiglia	Latent structure	Latent structure
Anno di origine	2007	1952–1968
Ideatore	Bruno D. Zumbo and colleagues	Frederic M. Lord (and Allan Birnbaum for the 2PL/3PL models)
Tipo	Internal consistency reliability estimation	Probabilistic measurement model
Fonte seminale	Zumbo, B. D., Gadermann, A. M. & Zeisser, C. (2007). Ordinal versions of coefficients alpha and theta as measures of internal consistency for Likert rating scales. Journal of Modern Applied Statistical Methods, 6(1), 21–29.	Lord, F. M. & Novick, M. R. (1968). Statistical Theories of Mental Test Scores. Addison-Wesley.
Alias	ordinal alpha, polychoric reliability, reliability for ordinal scales, ORA	IRT, latent trait theory, item characteristic curve theory, modern test theory
Correlati	5	5
Sintesi	Ordinal reliability analysis estimates the internal consistency of scales whose items are measured on ordered-category (Likert-type) response formats. By basing computations on polychoric correlations rather than Pearson correlations, it corrects for the attenuation that standard Cronbach's alpha produces when responses are discrete and non-normal.	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.