Σύγκριση μεθόδων

	Διαχρονική Λειτουργία Διαφορικών Στοιχείων (Longitudinal DIF)	Longitudinal IRT
Πεδίο	Ψυχομετρία	Ψυχομετρία
Οικογένεια	Latent structure	Latent structure
Έτος προέλευσης	1980s–2000s	1991
Δημιουργός	Multiple contributors; foundational DIF methods by Lord (1980) extended to longitudinal designs	Susan E. Embretson
Τύπος	Item-level bias detection across time	Latent trait / longitudinal psychometric model
Θεμελιώδης πηγή	Millsap, R. E., & Kwok, O. M. (2004). Evaluating the impact of partial factorial measurement invariance on selection in two groups. Psychological Methods, 9(1), 93–115.	Embretson, S. E. (1991). A multidimensional latent trait model for measuring learning and change. Psychometrika, 56(3), 495–515.
Εναλλακτικές ονομασίες	longitudinal DIF, DIF across time, temporal DIF, longitudinal item bias	LIRT, longitudinal IRT, repeated-measures IRT, dynamic item response modeling
Συναφείς	6	4
Σύνοψη	Longitudinal differential item functioning detects whether individual test or scale items behave differently across measurement occasions for the same respondents. It extends standard DIF methodology to repeated-measures designs, ensuring that observed change scores genuinely reflect construct change rather than shifts in item characteristics over time.	Longitudinal IRT extends classical item response theory to data collected at multiple time points, allowing researchers to model both the initial latent trait level and its change over time. It is used in educational assessment, clinical trials, and panel studies where the same items or item banks are administered repeatedly to the same individuals.