"There are large differences across countries in instructional time in schooling institutions. Can these differences explain some of the differences across countries in pupils' achievements in different subjects? While research in recent years provides convincing evidence about the effect of...

The wage premium for high-skilled workers in the United States, measured as the ratio of the 90th-to-10th percentiles from the wage distribution, increased by 20 percent from the 1970s to the late 1980s. A large literature has emerged to explain this phenomenon. A leading explanation is that...