手法を比較

	ラッシュモデル	2母数ロジスティックIRTモデル（2PL）
分野	心理測定学	心理測定学
系統	Latent structure	Latent structure
提唱年	1960	1980
提唱者	Georg Rasch	Frederic M. Lord
種類	Item Response Theory / Latent trait model	Item response model / latent trait model
原典	Rasch, G. (1960). Probabilistic Models for Some Intelligence and Attainment Tests. Danish Institute for Educational Research, Copenhagen.	Lord, F. M. (1980). Applications of Item Response Theory to Practical Testing Problems. Erlbaum.
別名	1PL IRT, one-parameter logistic model, Rasch Modeli — 1PL IRT, 1PL model	two-parameter logistic model, 2PL model, 2PL IRT — İki Parametreli Madde Tepki Modeli
関連	6	6
概要	The Rasch model, introduced by Georg Rasch in 1960, is the simplest member of the Item Response Theory (IRT) family. It assigns a single difficulty parameter to each test item and places both item difficulties and person abilities on the same logit scale, enabling direct, sample-independent comparison of items and persons.	The two-parameter logistic item response model, formalised by Frederic Lord (1980), describes the probability that a respondent answers a binary test item correctly as a smooth S-shaped function of the respondent's latent ability. By estimating a separate discrimination parameter for each item alongside a difficulty parameter, 2PL allows items to differ in how sharply they distinguish high- from low-ability respondents — making it the standard model for large-scale educational and psychological assessments.