Σύγκριση μεθόδων

	Συντελεστής Αξιοπιστίας Ωμέγα (ω) του McDonald	Μοντέλο Rasch
Πεδίο	Ψυχομετρία	Ψυχομετρία
Οικογένεια	Latent structure	Latent structure
Έτος προέλευσης	1999	1960
Δημιουργός	Roderick P. McDonald	Georg Rasch
Τύπος	Reliability coefficient / latent variable model	Item Response Theory / Latent trait model
Θεμελιώδης πηγή	McDonald, R. P. (1999). Test Theory: A Unified Treatment. Lawrence Erlbaum Associates. ISBN: 978-0805830750	Rasch, G. (1960). Probabilistic Models for Some Intelligence and Attainment Tests. Danish Institute for Educational Research, Copenhagen.
Εναλλακτικές ονομασίες	omega reliability, ω coefficient, omega total, omega hierarchical	1PL IRT, one-parameter logistic model, Rasch Modeli — 1PL IRT, 1PL model
Συναφείς	6	6
Σύνοψη	McDonald's omega is a factor-analysis-based reliability coefficient introduced by Roderick P. McDonald (1999) that quantifies the internal consistency of a composite score without requiring the restrictive assumption that all items contribute equally to the latent factor. It yields two complementary indices: ω_total, which captures overall reliability of the sum score, and ω_hierarchical (ωh), which reports how much of the composite's variance is explained specifically by a single general factor.	The Rasch model, introduced by Georg Rasch in 1960, is the simplest member of the Item Response Theory (IRT) family. It assigns a single difficulty parameter to each test item and places both item difficulties and person abilities on the same logit scale, enabling direct, sample-independent comparison of items and persons.