Over the past two decades, education underwent a "big data" revolution as states began tracking individual student performance and interim assessments and educational software allowed for a greater granularity of data on students, teachers, and schools. Despite this plethora of new data, considerable gaps in data on early childhood education, school spending, student program and intervention, and postsecondary outcomes remain. Dissatisfaction with education data will never fully disappear due to technical gaps between what policymakers and researchers would like to measure and what can be measured, as well as normative disagreements about what data should be collected. Policymakers should focus on closing the gaps they can while also recognizing the technical and normative constraints on educational measurement.