手法を比較

	順序型ラスクモデル（段階評価尺度モデルおよび部分信用モデル）	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	1978–1982	1952–1968
提唱者	David Andrich (RSM, 1978); Geoff Masters (PCM, 1982)	Frederic M. Lord (and Allan Birnbaum for the 2PL/3PL models)
種類	Item response model for ordered categories	Probabilistic measurement model
原典	Andrich, D. (1978). A rating formulation for ordered response categories. Psychometrika, 43(4), 561–573.	Lord, F. M. & Novick, M. R. (1968). Statistical Theories of Mental Test Scores. Addison-Wesley.
別名	Rating Scale Model, Partial Credit Model, RSM, PCM	IRT, latent trait theory, item characteristic curve theory, modern test theory
関連	6	5
概要	The ordinal Rasch model extends the dichotomous Rasch framework to items with ordered response categories such as Likert-type scales. It places both persons and items on a shared interval-level metric, enabling principled measurement from ordinal data while checking whether items function consistently across all response thresholds.	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.