Those figures are drawn from a 2024 study by Brown University economist Matthew Kraft, which also found that differences in instructional time between states can be dwarfed by those within states. By the end of elementary school, for example, Oregon students living in a district at the bottom of the state’s school time rankings receive a full 1.4 years less education than those in a district at the top. The gap explodes to nearly three years’ worth of instruction by the time those students graduate high school.