Methoden vergleichen

	Kurzform von McDonald's Omega	Item Response Theory (IRT)
Fachgebiet	Psychometrie	Psychometrie
Familie	Latent structure	Latent structure
Entstehungsjahr	1999 (omega); short-form application 1990s–2000s	1952–1968
Urheber	Roderick P. McDonald (omega); short-form application systematised across psychometric literature	Frederic M. Lord (and Allan Birnbaum for the 2PL/3PL models)
Typ	Reliability coefficient for abbreviated scales	Probabilistic measurement model
Wegweisende Quelle	McDonald, R. P. (1999). Test theory: A unified treatment. Lawrence Erlbaum Associates. ISBN: 978-0805830750	Lord, F. M. & Novick, M. R. (1968). Statistical Theories of Mental Test Scores. Addison-Wesley.
Aliasnamen	omega for abbreviated scales, short-scale omega, omega-total short form, abbreviated scale reliability	IRT, latent trait theory, item characteristic curve theory, modern test theory
Verwandt	4	5
Zusammenfassung	Short-form McDonald's omega applies the omega reliability coefficient to abbreviated or shortened versions of psychological scales. It provides a theoretically sound reliability estimate that accounts for the multidimensional structure of the short instrument, enabling researchers to evaluate whether abbreviation has preserved the reliability of the original full-length 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.