The Evolution of the Black-White Test Score Gap in Grades K-3: The Fragility of Results

Although both economists and psychometricians typically treat them as interval scales, test scores are reported using ordinal scales. Using the Early Childhood Longitudinal Study and the Children of the National Longitudinal Survey, we examine the effect of order-preserving scale transformations on the evolution of the black-white reading test score gap from kindergarten entry through third grade. Plausible transformations reverse the growth of the gap in the CNLSY and greatly mitigate it in the ECLS-K during early school years. All growth from entry through first grade and a nontrivial proportion from first to third grade probably reflects scaling decisions.