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ERIC Number: EJ1049765
Record Type: Journal
Publication Date: 2015
Pages: 17
Abstractor: As Provided
ISSN: ISSN-1530-5058
Modeling Local Item Dependence Due to Common Test Format with a Multidimensional Rasch Model
Baghaei, Purya; Aryadoust, Vahid
International Journal of Testing, v15 n1 p71-87 2015
Research shows that test method can exert a significant impact on test takers' performance and thereby contaminate test scores. We argue that common test method can exert the same effect as common stimuli and violate the conditional independence assumption of item response theory models because, in general, subsets of items which have a shared feature are a source of response dependence (Marais & Andrich, 2008). In this study, we use the Rasch testlet model (Wang & Wilson, 2005a) to examine the effect of test method on violating the unidimensionality assumption of the Rasch model. Results show that test formats can introduce small to large construct-irrelevant variance, contaminate test scores, and lead to the violation of the conditional independence assumption. Our findings further suggest that the degree of construct-irrelevant variance exerted by test method could be a function of test format familiarity.
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Publication Type: Journal Articles; Reports - Research
Education Level: Higher Education; Postsecondary Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A
Identifiers - Location: China; Iran; Malaysia; Philippines; Singapore
Identifiers - Assessments and Surveys: International English Language Testing System
Grant or Contract Numbers: N/A