The lesson its leaders have drawn is that a high income doesn't compensate for shortcomings in education. But that isn't the case. For example, one in four 15-year-olds in the United States does not successfully complete even the most basic tasks in PISA. So even high-income OECD countries would gain significantly if all of their students left school with at least basic knowledge and skills. For this group of countries, the average future GDP would be 3.5% higher than it would be without this improvement.