手法を比較

	順序項目応答理論	部分評点モデル（PCM / GPCM）
分野	心理測定学	心理測定学
系統	Latent structure	Latent structure
提唱年	1969	1982
提唱者	Fumiko Samejima (Graded Response Model, 1969); Gerhard Fischer & Georg Rasch lineage for partial credit	Geoff N. Masters (PCM, 1982); Eiji Muraki (GPCM, 1992)
種類	Probabilistic latent trait model for ordered polytomous responses	Item Response Theory / Polytomous IRT
原典	Samejima, F. (1969). Estimation of latent ability using a response pattern of graded scores. Psychometrika Monograph Supplement, 34(4, Pt. 2), 1–97.	Masters, G. N. (1982). A Rasch model for partial credit scoring. Psychometrika, 47(2), 149–174.
別名	polytomous IRT, ordinal IRT models, graded response models, ordinal latent trait models	Kısmi Kredi Modeli (PCM / GPCM), Generalized Partial Credit Model, GPCM, PCM
関連	6	5
概要	Ordinal item response theory (ordinal IRT) comprises a family of probabilistic models — most notably the Graded Response Model and the Partial Credit Model — that relate a respondent's standing on a latent trait to the probability of choosing each ordered response category on a polytomous item. It extends classical IRT beyond dichotomous items to the Likert-type and rating-scale items that dominate psychometric measurement.	The Partial Credit Model is an extension of the Rasch measurement framework designed for ordered polytomous items — items whose responses fall into more than two ordered categories, such as partial-credit tasks in performance assessment or open-ended scoring rubrics. Proposed by Geoff Masters in 1982 and later generalised by Eiji Muraki in 1992, the model estimates a separate threshold (step) parameter for each adjacent-category transition within every item, allowing fine-grained calibration of how much each additional credit level contributes to locating a person on the latent trait.