قارن الطرق

	التحليل التفاضلي للأداء الفقري الطولي (Longitudinal DIF)	نظرية الاستجابة للمفردة (IRT)
المجال	القياس النفسي	القياس النفسي
العائلة	Latent structure	Latent structure
سنة النشأة	1980s–2000s	1952–1968
صاحب الطريقة	Multiple contributors; foundational DIF methods by Lord (1980) extended to longitudinal designs	Frederic M. Lord (and Allan Birnbaum for the 2PL/3PL models)
النوع	Item-level bias detection across time	Probabilistic measurement model
المصدر التأسيسي	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.	Lord, F. M. & Novick, M. R. (1968). Statistical Theories of Mental Test Scores. Addison-Wesley.
الأسماء البديلة	longitudinal DIF, DIF across time, temporal DIF, longitudinal item bias	IRT, latent trait theory, item characteristic curve theory, modern test theory
ذات صلة	6	5
الملخص	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.	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.