Principles and Practices of Test Score Equating

Abstract

Score equating is essential for any testing program that continually produces new editions of a test and for which the expectation is that scores from these editions have the same meaning over time. Particularly in testing programs that help make high‐stakes decisions, it is extremely important that test equating be done carefully and accurately. An error in the equating function or score conversion can affect the scores for all examinees, which is both a fairness and a validity concern. Because the reported score is so visible, the credibility of a testing organization hinges on activities associated with producing, equating, and reporting scores. This paper addresses the practical implications of score equating by describing aspects of equating and best practices associated with the equating process.

Smoothing and Equating Methods Applied to Different Types of Test Score Distributions and Evaluated With Respect to Multiple Equating Criteria

“…Other works have approached these issues in different ways, sometimes promoting postsmoothing with cubic splines to avoid the complexities of systematic irregularities (Kolen, 2007, p. 53) and other times recommending that systematic irregularities be fit and then smoothed out based on statistical criteria (von Davier et al, 2004, p. 64). Beyond statistical criteria, pragmatic concerns about the visibility and interpretation of equating results and the interaction of equating results with scale score conversions also inform equating practice (Dorans, Moses, & Eignor, 2010). The use of smoothing and equating methods to address pragmatic concerns can mean that very smooth equating results may be preferred because these results produce the most interpretable reported scores and/or because they are more conservative ways of dealing with test data collected under less-than-perfect conditions.…”

Test equating for measuring system progress in longitudinal surveys of student academic achievement

“…It has also been argued that the link items should be spread out to cover different level of a scale continuum. In addition, the number of items must meet a minimum requirement [9].…”

“…The two literacy tests were developed using the same test blueprint [1] which meets the assumption and requirement of the Rasch model for test equating purpose [9]. The 2001 literacy test included 60 items while the 2007 literacy test included 40 items.…”

Contributions to Score Linking Theory and Practice

“…This framework was adapted for the public health domain by Dorans (2007) and served as the backbone for the volume on linking and aligning scores and scales by . Dorans et al (2010a) provided an overview of the particular type of score linking called score equating from a perspective of best practices. After defining equating as a special form of score linking, the authors described the most common data collection designs used in the equating of test scores, some common observed-score equating functions, common data-processing practices that occur prior to computations of equating functions, and how to evaluate an equating function.…”