Not Where You Start, but How Much You Grow

The Equality of Educational Opportunity Study (1966)—the Coleman Report—lodged a key takeaway in the minds of educators, researchers, and parents: Schools do not strongly shape students' achievement outcomes. This finding has been influential to the field; however, Coleman himself suggested that—had longitudinal data been available to him—decomposing the variance in students' growth rates rather than their levels of achievement would have provided a clearer insight into school effects. Inspired by an intriguing finding from an earlier study conducted in 1988 by Bryk and Raudenbush, we take up Coleman's suggestion using data provided by NWEA, which has administered over 200 million vertically scaled assessments across all 50 states since 2008. We replicated Bryk and Raudenbush's surprising finding that most of the variation in student learning rates lies between rather than within schools. For students moving from Grades 1 through 5, we found 75% (math) to 80% (English language arts) of the variance in achievement rates is at the school level. We find similar results in preliminary analyses of data from the Early Childhood Longitudinal Study-Kindergarten Class 1998-99 (ECLS-K:99). These results are intriguing because they call into question one of the dominant narratives about the extent to which schools shape students' achievement; however, more research is needed. Our goal is to invite other scholars to conduct similar analyses in other data contexts. We delineate four key dimensions along which results need to be further probed, first and foremost with an eye toward the role of test score scaling practices, which may be of central importance.