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 (ECLS-K) and the Children of the National Longitudinal Survey of Youth (CNLSY), we examine how order-preserving scale transformations affect 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 reduce it in the ECLS-K during the early school years. All growth from entry through first grade and a nontrivial proportion from first to third grade probably reflects scaling decisions.