Methoden vergleichen

	Ordinales Rasch-Modell (Rating Scale und Partial Credit Model)	Item Response Theory (IRT)
Fachgebiet	Psychometrie	Psychometrie
Familie	Latent structure	Latent structure
Entstehungsjahr	1978–1982	1952–1968
Urheber	David Andrich (RSM, 1978); Geoff Masters (PCM, 1982)	Frederic M. Lord (and Allan Birnbaum for the 2PL/3PL models)
Typ	Item response model for ordered categories	Probabilistic measurement model
Wegweisende Quelle	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.
Aliasnamen	Rating Scale Model, Partial Credit Model, RSM, PCM	IRT, latent trait theory, item characteristic curve theory, modern test theory
Verwandt	6	5
Zusammenfassung	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.