Confronta i metodi

	Sviluppo di Scale Politomiche	Teoria della risposta all'item (IRT)
Campo	Psicometria	Psicometria
Famiglia	Latent structure	Latent structure
Anno di origine	1969–1982	1952–1968
Ideatore	Samejima, F.; Masters, G. N. (independently)	Frederic M. Lord (and Allan Birnbaum for the 2PL/3PL models)
Tipo	Psychometric scale construction	Probabilistic measurement model
Fonte seminale	Embretson, S. E. & Reise, S. P. (2000). Item Response Theory for Psychologists. Lawrence Erlbaum Associates. ISBN: 978-0805828191	Lord, F. M. & Novick, M. R. (1968). Statistical Theories of Mental Test Scores. Addison-Wesley.
Alias	polytomous item development, ordered-category scale construction, rating scale development, multi-category item development	IRT, latent trait theory, item characteristic curve theory, modern test theory
Correlati	6	5
Sintesi	Polytomous scale development is the systematic construction and validation of measurement instruments whose items have three or more ordered response categories — such as Likert-type, rating, or partial-credit items. It applies polytomous item response theory models or ordinal factor analysis methods to evaluate item quality, estimate latent trait levels, and build a psychometrically sound scale.	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.