Education increases individual productivity and wages, as well as national growth in the long run. While education levels are linked to higher incomes, measuring its impact on macroeconomic growth is difficult due to data and endogeneity issues. Recent studies find that education quality, as assessed by tests like PISA and TIMSS, is a more significant predictor of growth than just years of schooling. Examinations show developing countries vary widely in student performance, with some like Shanghai and Singapore outperforming OECD averages while others have large shares below basic proficiency levels.