Σύγκριση μεθόδων

	Differential Item Functioning in Educational Testing	Διαφορική Λειτουργία Αντικειμένου (DIF)
Πεδίο	Education	Ψυχομετρία
Οικογένεια	Latent structure	Latent structure
Έτος προέλευσης	1993	1970s–1993
Δημιουργός	Educational measurement / test-fairness tradition (Holland, Wainer, Dorans, Thissen)	William H. Angoff and colleagues (ETS); systematized by Holland & Wainer
Τύπος	Test-fairness analysis detecting items that function differently across groups	Item-level bias detection
Θεμελιώδης πηγή	Holland, P. W., & Wainer, H. (Eds.). (1993). Differential Item Functioning. Lawrence Erlbaum Associates. ISBN: 9780805809725	Holland, P. W. & Wainer, H. (Eds.) (1993). Differential Item Functioning. Lawrence Erlbaum Associates. ISBN: 978-0805809589
Εναλλακτικές ονομασίες	Educational DIF Analysis, Item Bias Detection in Tests, Test Fairness DIF, Mantel-Haenszel DIF	DIF, item bias analysis, measurement non-equivalence, item-level measurement bias
Συναφείς	4	5
Σύνοψη	Differential item functioning (DIF) analysis is the central statistical tool for evaluating the fairness of test items in education. An item shows DIF when examinees of equal ability but different group membership — for example by gender, race/ethnicity, or language background — have unequal probabilities of answering it correctly. By conditioning on ability before comparing groups, DIF analysis separates genuine item bias from real group differences in proficiency, and flags items for expert review before they affect high-stakes decisions.	Differential item functioning identifies test or survey items that behave differently for examinees from different groups — such as gender, ethnicity, or language background — after controlling for the underlying ability or trait being measured. DIF analysis is essential for fairness evaluation in educational testing and psychological scale development.