Asymptotic Variance of Linking Coefficient Estimators for Polytomous IRT Models.

ABSTRACT: In item response theory (IRT), when two groups from different populations take two separate tests, there is a need to link the two ability scales so that the item parameters of the tests are comparable across the groups. To link the two scales, information from common items are utilized to estimate linking coefficients which place the item parameters on the same scale. For polytomous IRT models, the Haebara and Stocking-Lord methods for estimating the linking coefficients have commonly been recommended. However, estimates of the variance for these methods are not available in the literature. In this article, the asymptotic variance of linking coefficients for polytomous IRT models with the Haebara and Stocking-Lord methods are derived. The results are presented in a general form and specif

SUBMITTER: Andersson B 

PROVIDER: S-EPMC5985705 | biostudies-literature | 2018 May

REPOSITORIES: biostudies-literature