To address the lack of attention to construct shift in item response theory (IRT) vertical scaling, a multigroup, bifactor model was proposed to model the common dimension for all grades and the grade-specific dimensions. Bifactor model estimation accuracy was evaluated through a simulation study with manipulated factors of percentage of common…

This paper uses data from the National Education Longitudinal Study of 1988 (NELS:88) dataset to demonstrate practical examples of the ways in which the method used for centering level-1 variables in multilevel models affects the findings. Demonstrations compare raw metric scaling, grand mean centering, and group mean centering for successively…

This paper addresses issues of vertical equating for the Arkansas Comprehensive Testing, Assessment and Accountability Program (ACTAAP) assessments as they relate to school accountability and determination of Adequate Yearly Progress (AYP) as required by the recent federal legislation, the No Child Left Behind Act. The paper first provides a brief…

Describes the concept of "adequate yearly progress" as defined by the No Child Left Behind Act and discusses some of the psychometric issues it raises. Examines scaling as a means to equate tests when assessing educational gains and recommends vertically moderated standards over vertical equating of state assessments. (SLD)

This study examined how four commonly used test equating procedures (linear, equipercentile, Rasch Model, and three-parameter) would respond to situations in which the properties or the two tests being equated were different. Data for two tests plus an external anchor test were generated from a three parameter model in which mean test differences…

The purposes of this paper are: (1) to review some of the major studies of applications of item response theory (IRT) methodology to test equating and synthesize their results; (2) to discuss what questions are as yet unanswered and what problems exist with research methodology; and (3) to provide direction for future research. (Author/LMO)