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An Investigation of Possible Causes for the Inadequacy of IRT Pre-Equating IRT SAT

Eignor, Daniel R.; Stocking, Martha L.
Publication Year:
Report Number:
ETS Research Report
Document Type:
Page Count:
Subject/Key Words:
Equated Scores, Item Response Theory (IRT), Mathematical Models, Psychometrics, Scholastic Aptitude Test (SAT), Test Theory


A previous study of pre-equating the Scholastic Aptitude Test (SAT) using item response theory provided unacceptable equating results for SAT-mathematical data. The purpose of this study was to investigate two possible explanations for these unacceptable pre-equating results. Specifically, the calibration process, which made use of the three-parameter model and LOGIST, and the linking procedure used to place parameter estimates on the same scale were further investigated in a two-stage process to see if either was responsible for the poor IRT pre-equating results found for the SAT-mathematical data in the previous study. (50pp.)

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