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Does Preequating Work? An Investigation Into a Preequated Testlet-Based College Placement Exam Using Postadministration Data IRT

Gao, Rui; He, Wei; Ruan, Chunyi
Publication Year:
Report Number:
ETS Research Report
Document Type:
Page Count:
Subject/Key Words:
Item Response Theory (IRT), IRT Preequating, IRT True Score Equating, Observed-Score Equating, IRT Postequating


In this study, we investigated whether preequating results agree with equating results that are based on observed operational data (postequating) for a college placement program. Specifically, we examined the degree to which item response theory (IRT) true score preequating results agreed with those from IRT true score postequating and from observed score equating. Three academic subjects were examined in this study: analyzing and interpreting literature, American government, and college algebra. The findings suggested that differences between equating results from IRT true score preequating and postequating varied from subject to subject. In general, IRT true score postequating agreed with IRT true score preequating for most of the forms for a test subject. Any difference among the equating results can be attributed to the way through which items were pretested, contextual/order effects, or the violation of IRT assumptions.

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