Confronta i metodi

	Analisi di item politomici	Modello a Credito Parziale (PCM / GPCM)
Campo	Psicometria	Psicometria
Famiglia	Latent structure	Latent structure
Anno di origine	1969–1982	1982
Ideatore	Fumiko Samejima (graded response model, 1969); David Andrich (rating scale model, 1978); Geoffrey Masters (partial credit model, 1982)	Geoff N. Masters (PCM, 1982); Eiji Muraki (GPCM, 1992)
Tipo	Item-level psychometric analysis	Item Response Theory / Polytomous IRT
Fonte seminale	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.
Alias	ordered-category item analysis, graded response analysis, polytomous IRT, rated-scale item analysis	Kısmi Kredi Modeli (PCM / GPCM), Generalized Partial Credit Model, GPCM, PCM
Correlati	4	5
Sintesi	Polytomous item analysis examines the psychometric behavior of items that have more than two ordered response categories — such as Likert-type scales or partial-credit tasks. It evaluates each item's difficulty thresholds, discriminating power, and category functioning to determine whether the full response scale is being used as intended and whether each item contributes reliably to measuring the underlying construct.	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.