I use a dynamic augmented Solow model to estimate the effect of international test scores and investment in schooling and tutoring on economic growth rates in 55 countries during 1985-2005. Either test scores or investment in schooling and tutoring can explain growth rates in the full data set or in countries that had less than 8 years of schooling in 1985. In countries with more schooling in 1985, investment in schooling has a small effect and test scores have no effect on growth rates. In the 24 countries with scores above 470, higher scores have no effect on growth rates.