방법 비교

	순서형 문항 반응 이론	차별 문항 기능(Differential Item Functioning, DIF)
분야	심리측정학	심리측정학
계열	Latent structure	Latent structure
기원 연도	1969	1970s–1993
창시자	Fumiko Samejima (Graded Response Model, 1969); Gerhard Fischer & Georg Rasch lineage for partial credit	William H. Angoff and colleagues (ETS); systematized by Holland & Wainer
유형	Probabilistic latent trait model for ordered polytomous responses	Item-level bias detection
원전	Samejima, F. (1969). Estimation of latent ability using a response pattern of graded scores. Psychometrika Monograph Supplement, 34(4, Pt. 2), 1–97.	Holland, P. W. & Wainer, H. (Eds.) (1993). Differential Item Functioning. Lawrence Erlbaum Associates. ISBN: 978-0805809589
별칭	polytomous IRT, ordinal IRT models, graded response models, ordinal latent trait models	DIF, item bias analysis, measurement non-equivalence, item-level measurement bias
관련	6	5
요약	Ordinal item response theory (ordinal IRT) comprises a family of probabilistic models — most notably the Graded Response Model and the Partial Credit Model — that relate a respondent's standing on a latent trait to the probability of choosing each ordered response category on a polytomous item. It extends classical IRT beyond dichotomous items to the Likert-type and rating-scale items that dominate psychometric measurement.	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.