Congress passed the Every Student Succeeds Act, supplanting No Child Left Behind and placing responsibility for public school improvement squarely upon each of the 50 states. With the federal government's role in school accountability sharply diminished, it now falls to state and local governments to take decisive action. Even though most education policy debates have focused on school quality and student achievement, most research on the economic impact of schooling has focused narrowly on the number of years students remain in the educational system. This metric is not an adequate measure of student achievement and thus not a reliable indicator of economic impacts: it hardly matters how long one sits at a school desk if one learns little while occupying that seat. Recently, mounting evidence has suggested that measures of individual cognitive skills that incorporate dimensions of test-score performance provide much better indicators of economic outcomes--while also aligning the research with the policy deliberations. The importance of including direct measures of achievement is especially apparent when looking at differences in economic growth across states. In this essay, the authors document the long-term economic impact of a state's student-achievement levels, which in turn permits them to calculate the economic returns from school improvement. First, they show that in the 40 years between 1970 and 2010, the spread among the states in their per-capita gross domestic product (GDP) widened considerably. Next, they show that the level of student achievement is a strong predictor of the state's growth rate in GDP per capita over that time period, even after accounting for both the standard measure of school attainment and other economic factors. Finally, the authors project for each state the large positive impact that improvements in student achievement would have on a state's GDP. Any state political leader of vision would do well to make school quality a high priority