On the finiteness and uniqueness of the weighted likelihood estimator of ability in polytomous IRT models

Magis, David; Verhelst, Norman

Reference : On the finiteness and uniqueness of the weighted likelihood estimator of ability in p...


	Document type :	Scientific congresses and symposiums : Unpublished conference/Abstract
	Discipline(s) :	Social & behavioral sciences, psychology : Education & instruction
	To cite this reference:	http://hdl.handle.net/2268/173233

Title :	On the finiteness and uniqueness of the weighted likelihood estimator of ability in polytomous IRT models
Language :	English
Author, co-author :	Magis, David [Université de Liège - ULiège > Département Education et formation > Psychométrie et édumétrie >]
	Verhelst, Norman []
Publication date :	21-Nov-2014
Peer reviewed :	Yes
On invitation :	No
Audience :	International
Event name :	RCEC workshop on Item Response Theory and Educational Measurement
Event date :	19-21 novembre 2014
Event organizer :	Research Center for Examinations and Certification
Event place (city) :	Twente
Event country :	Pays-Bas
Keywords :	[en] Item response theory ; polytomous models ; weighted likelihood estimation ; finiteness ; uniqueness
Abstract :	[en] In item response theory (IRT), the weighted likelihood (WL) estimator has become a central method to estimate ability levels of respondents. Primarily introduced with dichotomous IRT models (Warm, 1989), it was later extended to polytomous IRT models (Samejima, 1998). However, very few information is available about the behavior of the WL estimator, and especially about the uniqueness of the ability estimates as well as their finiteness. The purpose of this talk is to establish that with polytomous item response models, the WL estimator of ability always returns finite values. This result is valid for the class of difference models and divide-by-total models, independently of the number of items and the response patterns. However, such estimates may not necessarily be unique, as the WL solving equation may provide several optimal values. Some examples are considered to illustrate both findings.
Permalink :	http://hdl.handle.net/2268/173233

File(s) associated to this reference

Additional material(s):

	File	Commentary	Size	Access
Private access	RCEC 2014 - David Magis.pdf		1.32 MB	Request copy
Private access	R code RCEC talk.R		416 B	Request copy

All documents in ORBi are protected by a user license.

Dspace v1.5