Assessment of Person Fit for Mixed-Format Tests. (August 2015)

• Record Type: Journal Article
• Authors: Sinharay, Sandip
• Is Part Of: Journal of educational and behavioral statistics. Volume 40:Number 4(2015)
• Page Start: 343
• Page End: 365
• Publication Date: 2015-08
• Subjects: three-parameter logistic model -- generalized partial credit model -- item response theory model fit -- posterior predictive model checking; Educational statistics -- Periodicals; Social sciences -- Statistical methods -- Periodicals; 370.2
• DOI: 10.3102/1076998615589128
• Languages: English
• ISSNs: 1076-9986

Abstract

Person-fit assessment may help the researcher to obtain additional information regarding the answering behavior of persons. Although several researchers examined person fit, there is a lack of research on person-fit assessment for mixed-format tests. In this article, the lz statistic and the ζ2 statistic, both of which have been used for tests with only dichotomous items or with only polytomous items, were modified for use with mixed-format tests. In a detailed simulation, the lz and ζ2 statistics are found to be conservative under a (frequentist) asymptotic normal approximation. However, the use of the statistics along with the (Bayesian) posterior predictive model checking method leads to a larger power. The suggested approaches are applied to an operational data set. The approaches appear to be satisfactory tools for assessing person fit for mixed-format tests.