השוואת שיטות

	מודל רָאש הסדרתי (מודל סולם הדירוג ומודל קרדיט חלקי)	תפקוד פריט דיפרנציאלי (DIF)
תחום	פסיכומטריה	פסיכומטריה
משפחה	Latent structure	Latent structure
שנת המקור	1978–1982	1970s–1993
הוגה השיטה	David Andrich (RSM, 1978); Geoff Masters (PCM, 1982)	William H. Angoff and colleagues (ETS); systematized by Holland & Wainer
סוג	Item response model for ordered categories	Item-level bias detection
מקור מכונן	Andrich, D. (1978). A rating formulation for ordered response categories. Psychometrika, 43(4), 561–573.	Holland, P. W. & Wainer, H. (Eds.) (1993). Differential Item Functioning. Lawrence Erlbaum Associates. ISBN: 978-0805809589
כינויים	Rating Scale Model, Partial Credit Model, RSM, PCM	DIF, item bias analysis, measurement non-equivalence, item-level measurement bias
קשורות	6	5
תקציר	The ordinal Rasch model extends the dichotomous Rasch framework to items with ordered response categories such as Likert-type scales. It places both persons and items on a shared interval-level metric, enabling principled measurement from ordinal data while checking whether items function consistently across all response thresholds.	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.