Exploring the Full-information Bifactor Model in Vertical Scaling with Construct Shift

dc.contributor.advisorLissitz, Robert W.en_US
dc.contributor.authorLi, Yingen_US
dc.contributor.departmentMeasurement, Statistics and Evaluationen_US
dc.contributor.publisherDigital Repository at the University of Marylanden_US
dc.contributor.publisherUniversity of Maryland (College Park, Md.)en_US
dc.date.accessioned2011-07-07T05:32:59Z
dc.date.available2011-07-07T05:32:59Z
dc.date.issued2011en_US
dc.description.abstractTo address the lack of attention to construct shift in IRT vertical scaling, a bifactor model is proposed to estimate the common dimension for all grades and the grade-specific dimensions. The bifactor model estimation accuracy is evaluated through a simulation study with manipulated factors of percent of common items, sample size, and degree of construct shift. In addition, the unidimensional IRT (UIRT) estimation model that ignores construct shift is examined to represent the current practice for IRT vertical scaling; comparisons on parameter estimation accuracy of the bifactor and UIRT models are discussed. The major findings of the simulation study are (1) bifactor models are well recovered overall, even though item discrimination parameters are underestimated to a small degree; (2) item discrimination parameter estimates are overestimated in UIRT models due to the effect of construct shift; (3) person parameters of UIRT models are less accurately estimated than that of bifactor models, and the accuracy decreases as the degree of construct shift increases; (4) group mean parameter estimates of UIRT models are less accurate than that of bifactor models, and a large effect due to construct shift is found for the group mean parameter estimates of UIRT models. The real data analysis provides an illustration of how bifactor models can be applied to a problem involving for vertical scaling with construct shift. General procedures for testing practice are also discussed.en_US
dc.identifier.urihttp://hdl.handle.net/1903/11632
dc.subject.pqcontrolledEducational Tests and Measurementsen_US
dc.subject.pquncontrolledBifactor modelen_US
dc.subject.pquncontrolledConstruct shiften_US
dc.subject.pquncontrolledIRTen_US
dc.subject.pquncontrolledItem Resonse Theoryen_US
dc.subject.pquncontrolledK-12 assessmentsen_US
dc.subject.pquncontrolledVertical scalingen_US
dc.titleExploring the Full-information Bifactor Model in Vertical Scaling with Construct Shiften_US
dc.typeDissertationen_US
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