手法を比較

	一般化可能性理論（G理論）	2母数ロジスティックIRTモデル（2PL）
分野	心理測定学	心理測定学
系統	Latent structure	Latent structure
提唱年	1963	1980
提唱者	Lee J. Cronbach and colleagues	Frederic M. Lord
種類	ANOVA-based variance-component framework	Item response model / latent trait model
原典	Brennan, R. L. (2001). Generalizability Theory. Springer.	Lord, F. M. (1980). Applications of Item Response Theory to Practical Testing Problems. Erlbaum.
別名	Generalizability Theory, G-Study / D-Study framework, Genellenebilirlik Kuramı (G-Kuramı)	two-parameter logistic model, 2PL model, 2PL IRT — İki Parametreli Madde Tepki Modeli
関連	6	6
概要	Generalizability Theory, developed by Lee J. Cronbach and colleagues in the 1960s and formalised by Brennan (2001), is an ANOVA-based framework that extends Classical Test Theory by decomposing observed score variance into multiple, separately identified sources of measurement error — such as raters, tasks, occasions, or items — rather than bundling all error into a single undifferentiated term.	The two-parameter logistic item response model, formalised by Frederic Lord (1980), describes the probability that a respondent answers a binary test item correctly as a smooth S-shaped function of the respondent's latent ability. By estimating a separate discrimination parameter for each item alongside a difficulty parameter, 2PL allows items to differ in how sharply they distinguish high- from low-ability respondents — making it the standard model for large-scale educational and psychological assessments.