The Metric Matters: The Sensitivity of Conclusions About Growth in Student Achievement to Choice of Metric

Abstract

A central means of assessing the health of educational systems involves using longitudinal data to examine patterns of academic growth across a series of grades (e.g., the extent to which the range of achievement among students widens or narrows over time and whether students tend to “slump” in particular grades). The purpose of this article is to illustrate, through a series of analyses based on a longitudinal study of reading achievement in the Chicago Public Schools, that the conclusions one draws about patterns of academic growth and, in turn, the decisions one makes regarding the kinds of interventions that may be needed can be extremely sensitive to the metric used (i.e., whether achievement is measured using grade equivalents or based on item response theory metrics).