手法を比較

	部分評点モデル（PCM / GPCM）	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	1982	1952–1968
提唱者	Geoff N. Masters (PCM, 1982); Eiji Muraki (GPCM, 1992)	Frederic M. Lord (and Allan Birnbaum for the 2PL/3PL models)
種類	Item Response Theory / Polytomous IRT	Probabilistic measurement model
原典	Masters, G. N. (1982). A Rasch model for partial credit scoring. Psychometrika, 47(2), 149–174.	Lord, F. M. & Novick, M. R. (1968). Statistical Theories of Mental Test Scores. Addison-Wesley.
別名	Kısmi Kredi Modeli (PCM / GPCM), Generalized Partial Credit Model, GPCM, PCM	IRT, latent trait theory, item characteristic curve theory, modern test theory
関連	5	5
概要	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.	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.