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TITLE:
Using Expected Growth Size Estimates To Summarize Test Score Changes. ERIC/AE Digest.

DOCUMENT TYPE: Report

Link to Document: Using Expected Growth Size Estimates To Summarize Test Score Changes. ERIC/AE Digest.

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ABSTRACT:
An earlier Digest described the shortcomings of three methods commonly used to summarize changes in test scores. This Digest describes two less commonly used approaches for examining changes in test scores, those of Standardized Growth Estimates and Effect Sizes. Aspects of these two approaches are combined and applied to the Iowa Test of Basic Skills to demonstrate the usefulness of a third method, termed Expected Growth Size, to examine change in test scores. An expected growth size is more difficult to calculate than the other methods, but it offers three advantages. By expressing change in relation to the standard deviation, growth rates for different tests and different grade levels can be compared directly. Once expected growth sizes are calculated for a given test, they can be transformed easily to more common measurement scales. And once expected growth sizes are transformed to a Normal Curve Equivalent scale, changes in an individual's or a group's mean score can be reported in relation to expected growth. How to calculate expected growth size is illustrated. (SLD)