مقایسهٔ روش‌ها

	مدل رایش چند مقوله ای	عملکرد افتراقی آیتم (DIF)
حوزه	روان‌سنجی	روان‌سنجی
خانواده	Latent structure	Latent structure
سال پیدایش	1978–1982	1970s–1993
پدیدآور	Gerhard N. Masters (Partial Credit Model); David Andrich (Rating Scale Model)	William H. Angoff and colleagues (ETS); systematized by Holland & Wainer
نوع	Item response model	Item-level bias detection
منبع بنیادین	Masters, G. N. (1982). A Rasch model for partial credit scoring. Psychometrika, 47(2), 149–174.	Holland, P. W. & Wainer, H. (Eds.) (1993). Differential Item Functioning. Lawrence Erlbaum Associates. ISBN: 978-0805809589
نام‌های دیگر	PRM, Rating Scale Model, Partial Credit Model, Polytomous IRT Rasch	DIF, item bias analysis, measurement non-equivalence, item-level measurement bias
مرتبط	6	5
خلاصه	The Polytomous Rasch Model extends the dichotomous Rasch framework to ordered response scales with three or more categories, such as Likert items or partial-credit tasks. It estimates person ability and item difficulty on the same interval-level logit scale, and it tests whether the response categories function as intended — prerequisites for rigorous ordinal 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.