مقایسهٔ روش‌ها

	نظریه تعمیم‌پذیری (G-Theory)	مدل لجستیک دو پارامتری نظریه پاسخ به سؤال (2PL)	آلفای کرونباخ (تحلیل پایایی)
حوزه	روان‌سنجی	روان‌سنجی	آمار
خانواده	Latent structure	Latent structure	Latent structure
سال پیدایش	1963	1980	1951
پدیدآور	Lee J. Cronbach and colleagues	Frederic M. Lord	Lee J. Cronbach
نوع	ANOVA-based variance-component framework	Item response model / latent trait model	Reliability / internal consistency coefficient
منبع بنیادین	Brennan, R. L. (2001). Generalizability Theory. Springer.	Lord, F. M. (1980). Applications of Item Response Theory to Practical Testing Problems. Erlbaum.	Cronbach, L. J. (1951). Coefficient alpha and the internal structure of tests. Psychometrika, 16(3), 297–334.
نام‌های دیگر	Generalizability Theory, G-Study / D-Study framework, Genellenebilirlik Kuramı (G-Kuramı)	two-parameter logistic model, 2PL model, 2PL IRT — İki Parametreli Madde Tepki Modeli	coefficient alpha, alpha reliability, internal consistency reliability, Güvenilirlik Analizi (Cronbach Alpha)
مرتبط	6	6	4
خلاصه	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.	Cronbach's alpha is a coefficient of internal consistency that quantifies the degree to which a set of items on a scale measures the same underlying construct. Introduced by Lee J. Cronbach in 1951, it remains the most widely reported reliability index in social-science, health, and educational research.