手法を比較

	ロバストなマクドナルドのオメガ	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	1999 (omega); robust variant formalized in 2000s–2010s	1952–1968
提唱者	Roderick P. McDonald (omega); robust extension via robust SEM estimators (MLR, DWLS)	Frederic M. Lord (and Allan Birnbaum for the 2PL/3PL models)
種類	Reliability coefficient	Probabilistic measurement model
原典	McDonald, R. P. (1999). Test theory: A unified treatment. Lawrence Erlbaum Associates. ISBN: 978-0805830408	Lord, F. M. & Novick, M. R. (1968). Statistical Theories of Mental Test Scores. Addison-Wesley.
別名	robust omega, omega total (robust), robust omega-total, robust composite reliability	IRT, latent trait theory, item characteristic curve theory, modern test theory
関連	4	5
概要	Robust McDonald's omega estimates the internal consistency reliability of a composite scale using factor-analytic loadings obtained through robust estimation methods (such as MLR or DWLS). Unlike standard omega or Cronbach's alpha, it remains accurate when item distributions are non-normal, skewed, or when the sample contains influential outliers — conditions common in applied psychological and educational measurement.	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.