With all the competition to get into the right universities to secure the best jobs, secondary school students are often encouraged to take after-school classes in subjects already taught in school to help them improve their performance – even if that means forsaking other fun and interesting ways of spending after-school hours, such as playing sports, taking music lessons or volunteering at a local community centre or hospital. Students in the OECD area spend an average of nearly two-and-a-half hours per week in after-school lessons. In Greece, Israel, Korea, Turkey and the partner countries Azerbaijan, Kyrgyzstan, Qatar and Tunisia, students spend over four-and-a-half hours per week in such classes. Does that investment in after-school classes pay off?...