In some countries and economies, such as Beijing-Shanghai-Jiangsu-Guangdong (China), Qatar,Thailand, Tunisia and the United Arab Emirates, students spend at least 54 hours per week learning at and outside of school combined, whereas in others, like Finland, Germany, Sweden, Switzerland and Uruguay, students spend less than 40 hours studying.

Students in Australia, Estonia, Finland, Germany, Japan, the Netherlands, New Zealand, Sweden and Switzerland show the best balance between total learning time and academic performance.

In school systems where students spend more time in regular science lessons, average science scores are higher; but when students spend more time studying science after school, average science scores are lower.