This is a not-so-complicated question. Effective teaching requires collaboration with colleagues, and in the U.S., this time is too limited. In Singapore and Shanghai, teachers work 40 hours a week—but they spend just 10 to 18 of those hours teaching. They use the remaining time to collaborate with colleagues and improve their practice. Compare that with the U.S., where educators teach 25 to 32 hours per week.
Less in class time for all teachers.