Publications & Resources
Changes in the Black-White Test Score Gap in the Elementary School Grades
Daniel Koretz and Young-Suk Kim
In a pair of recent studies, Fryer and Levitt (2004a, 2004b) analyzed the Early Childhood Longitudinal Study—Kindergarten Cohort (ECLS-K) to explore the characteristics of the Black-White test score gap in young children. They found that the gap grew markedly between kindergarten and the third grade and that they could predict the gap from measured characteristics in kindergarten but not in the third grade. In addition, they found that the widening of the gap was differential across areas of knowledge and skill, with Blacks falling behind in all areas other than the most basic. They raised the possibility that Black and Whites may not be on “parallel trajectories” and that Blacks, as they go through school, may never master some skills mastered by Whites.
This study re-analyzes the ECLS-K data to address this last question. We find that the scores used by Fryer and Levitt (proficiency probability scores, or PPS) do not support the hypothesis of differential growth of the gap. The patterns they found reflect the nonlinear relationships between overall proficiency, ?, and the PPS variables, as well as ceiling effects in the PPS distributions. Moreover, ? is a sufficient statistic for the PPS variables, and therefore, PPS variables merely re-express the overall mean difference between groups and contain no information about qualitative differences in performance between Black and White students at similar levels of ?. We therefore carried out differential item functioning (DIF) analyses of all items in all rounds of the ECLS-K through grade 5 (Round 6), excluding only the fall of grade 1 (which was a very small sample) and subsamples in which there were too few Black students for reasonable analysis. We found no relevant patterns in the distribution of the DIF statistics or in the characteristics of the items showing DIF that support the notion of differential divergence, other than in kindergarten and the first grade, where DIF favoring Blacks tended to be on items tapping simple skills taught outside of school (e.g., number recognition), while DIF disfavoring Blacks tended to be on material taught more in school (e.g., arithmetic). However, there were exceptions to this. Moreover, because of its construction and reporting, the ECLS-K data were not ideal for addressing this question, and data better suited to the purpose might show differential divergence across areas of knowledge and skill. The paper concludes by advising secondary analysts examining this question to be wary of aspects of test design that may influence the results and to be sensitive to likely variations in findings across databases.
Koretz, D., & Kim, Y.-S. (2007). Changes in the Black-White test score gap in the elementary school grades (CSE Report 715). Los Angeles: University of California, Los Angeles, National Center for Research on Evaluation, Standards, and Student Testing (CRESST).