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ERIC Number: ED507813
Record Type: Non-Journal
Publication Date: 2009-Dec
Pages: 17
Abstractor: As Provided
Reference Count: 14
Three Multidimensional Models for Testlet-Based Tests: Formal Relations and an Empirical Comparison. Research Report. ETS RR-09-37
Rijmen, Frank
Educational Testing Service
Three multidimensional item response theory (IRT) models for testlet-based tests are described. In the bifactor model (Gibbons & Hedeker, 1992), each item measures a general dimension in addition to a testlet-specific dimension. The testlet model (Bradlow, Wainer, & Wang, 1999) is a bifactor model in which the loadings on the specific dimensions are restricted to be proportional to the loadings on the general dimension within each testlet (Li, Bolt, & Fu, 2006). In the second-order model, the items only load on the testlet-specific factors. The correlations between the testlet-specific factors are modeled through a second-order factor. The second-order model is formally equivalent to the testlet model. The models were applied to a testlet-based international English assessment test. (Contains 6 figures and 1 table.)
Educational Testing Service. Rosedale Road Mailstop 19R, Princeton, NJ 08541-0001. Tel: 609-921-9000; Fax: 609-734-5410; Web site:
Publication Type: Reports - Evaluative
Education Level: N/A
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: Educational Testing Service