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	Graded Response Model (GRM)	ラッシュモデル
分野	心理測定学	心理測定学
系統	Latent structure	Latent structure
提唱年	1969	1960
提唱者	Fumiko Samejima	Georg Rasch
種類	Item response theory / polytomous IRT model	Item Response Theory / Latent trait model
原典	Samejima, F. (1969). Estimation of Latent Ability Using a Response Pattern of Graded Scores. Psychometrika Monograph Supplement, No. 17.	Rasch, G. (1960). Probabilistic Models for Some Intelligence and Attainment Tests. Danish Institute for Educational Research, Copenhagen.
別名	Samejima's GRM, Derecelendirilmiş Tepki Modeli (GRM), graded IRT model	1PL IRT, one-parameter logistic model, Rasch Modeli — 1PL IRT, 1PL model
関連	7	6
概要	The Graded Response Model is an item response theory model developed by Fumiko Samejima in 1969 for ordered polytomous items such as Likert-type scales. It estimates both the discriminating power of each item and a set of threshold parameters marking the boundaries between adjacent response categories, while simultaneously placing persons on a continuous latent trait scale.	The Rasch model, introduced by Georg Rasch in 1960, is the simplest member of the Item Response Theory (IRT) family. It assigns a single difficulty parameter to each test item and places both item difficulties and person abilities on the same logit scale, enabling direct, sample-independent comparison of items and persons.