Although some studies have investigated the impact of data-based decision making (DBDM) on student achievement, the overall findings are not straightforward, because of the studies’ methodological flaws and their mixed results. This article first presents a breakdown of the DBDM concept as applied in the Dutch context. Next, it explains the theoretical foundations of DBDM in feedback and goal-setting theory and then discusses various factors influencing DBDM effectiveness. The results of six Dutch DBDM interventions with an explicit focus on student achievement effects of DBDM and with strong research designs are then presented. Significant positive effects on student performance as measured by means of standardized tests are reported for f...