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	Analisi di affidabilità politoma	Analisi di Affidabilità Ordinale
Campo	Psicometria	Psicometria
Famiglia	Latent structure	Latent structure
Anno di origine	2007–2009 (formal ordinal extensions); broader framework since 1950s	2007
Ideatore	Building on Cronbach (1951) and McDonald (1978); ordinal extensions by Zumbo and colleagues (2007) and Green and Yang (2009)	Bruno D. Zumbo and colleagues
Tipo	Reliability estimation	Internal consistency reliability estimation
Fonte seminale	Green, S. B. & Yang, Y. (2009). Reliability of summed item scores using structural equation modeling: An alternative to coefficient alpha. Psychometrika, 74(1), 155–167.	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.
Alias	polytomous scale reliability, ordinal reliability estimation, reliability for ordered-category items, polychoric reliability analysis	ordinal alpha, polychoric reliability, reliability for ordinal scales, ORA
Correlati	3	5
Sintesi	Polytomous reliability analysis estimates the internal consistency or precision of measurement for scales composed of items with more than two ordered response categories, such as Likert-type, rating, or partial-credit items. It corrects a well-known underestimation bias in conventional Cronbach's alpha by working with polychoric correlations or IRT-based precision indices.	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.