This paper presents evidence that students´ test scores at ages 9 to 15 are not a good proxy for a nation´s stock of human capital. Across countries test scores rise with increases in human capital up to $40,000/adult (2000$), but then decline as human capital increases up to $125,000/adult....

This paper challenges Hanushek and Woessmann’s [2008] contention that the quality and not the quantity of schooling determines a nation’s rate of economic growth. I first show that their statistical analysis is flawed. I then show that when a nation’s average test scores and average...