Schooling attainment, schooling expenditures, and test scores what causes economic growth?

Using a dynamic augmented Solow model, I estimate the effect of students’ schooling attainment, schooling expenditures, and students’ test scores on growth rates over the period 1985-2005. I also estimate the effect of related measures for human capital stocks on national income in a static model in 2005. Individually all of the measures cause growth, and when included in the same model, more than one is statistically significant. Relative measurement error appears to determine which measure provides the best results. The results support the importance of increases in human capital for growth and the validity of the augmented Solow model