Adolescents’ academic performance is related in crucial ways to their family relationships (1), friendships (2), work patterns (3) and leisure patterns (4). Cultural beliefs are important in determining what is required from adolescents academically. Adolescents in developed countries started going to secondary school about a century ago. Schooling became the normative experience for adolescence. The same pattern is observed in developing countries but at a delayed rate. Adolescents being in school is a direct consequence of economic development. The content of secondary school has changed over time as well. There was no specific economic purpose of the curriculum in the 19th century but this changed as more adolescents started attending school. Schools started to focus more on training for work and citizenship. The comprehensive high school includes classes in general education, college preparation and vocational training. Many European countries have three types of secondary schools:College-preparatory schoolThis school offers a variety of academic courses and the goal is general education. It does not include classes on recreational subjects.Vocational schoolThis school prepares adolescents for a specific occupation.Professional schoolThis school prepares adolescents for a specific purpose (e.g. teacher training; arts).In this European system, adolescents need to decide relatively early what kind of future they envision. A later choice is likely more beneficial for adolescents. However, putting adolescents with different interests and educational levels together makes it more difficult for teachers to provide effective teaching. It can also be frustrating for adolescents who do have a specific idea of their future.Rates of secondary school enrolment vary widely among developing countries. The economy is often not industrialized which makes school-based knowledge of limited use. In China and Japan, admission to university is...