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An Analysis of Similarities in Item Functioning Within Antonym and Analogy Variant Families GRE CAT IRT

Scrams, David J.; Mislevy, Robert J.; Sheehan, Kathleen M.
Publication Year:
Report Number:
RR-02-13, GREB-97-17aP
ETS Research Report
Document Type:
Page Count:
Subject/Key Words:
Graduate Record Examination (GRE), Computerized Adaptive Testing (CAT), Item Response Theory (IRT), Item Varients, Expected Response Function, Item Calibration


This study examined the potential advantages of using item variants -- sets of related test items based on a common template or schema -- to offset the increased item-production demands associated with continuous computer-based testing in high-stakes assessments. Empirical results showed that the calibrated difficulty parameters of analogy and antonym item variants that had been used in operational administrations of the Graduate Record Examinations (GRE) General Test were very similar. Results of a simulation study that considered precision losses within a linear testing framework projected precision losses of less than 10% for estimating examinee abilities from responses to variants when using expected response functions based just on variant-family information, compared to using true item response theory parameters for individual items.

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