เปรียบเทียบวิธี

	Longitudinal DIF	ทฤษฎีการตอบสนองข้อสอบ (IRT)
สาขาวิชา	การวัดทางจิตวิทยา	การวัดทางจิตวิทยา
ตระกูล	Latent structure	Latent structure
ปีกำเนิด	1980s–2000s	1952–1968
ผู้ริเริ่ม	Multiple contributors; foundational DIF methods by Lord (1980) extended to longitudinal designs	Frederic M. Lord (and Allan Birnbaum for the 2PL/3PL models)
ประเภท	Item-level bias detection across time	Probabilistic measurement model
แหล่งต้นตำรับ	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.
ชื่อเรียกอื่น	longitudinal DIF, DIF across time, temporal DIF, longitudinal item bias	IRT, latent trait theory, item characteristic curve theory, modern test theory
ที่เกี่ยวข้อง	6	5
สรุป	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.