手法を比較

	順序尺度信頼性分析	項目応答理論 (IRT)
分野	心理測定学	心理測定学
系統	Latent structure	Latent structure
提唱年	2007	1952–1968
提唱者	Bruno D. Zumbo and colleagues	Frederic M. Lord (and Allan Birnbaum for the 2PL/3PL models)
種類	Internal consistency reliability estimation	Probabilistic measurement model
原典	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.
別名	ordinal alpha, polychoric reliability, reliability for ordinal scales, ORA	IRT, latent trait theory, item characteristic curve theory, modern test theory
関連	5	5
概要	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.