The majority of the macroeconomic literature on economic
returns to education employs measures of the quantity
of schooling. The most common measure is years of
schooling, averaged across the working-age population.
(Woessmann (2003) surveys issues of measuring and specifying
human capital from early growth accounting to
current cross-country growth regressions.) The standard
method of estimating the effect of education on economic
growth is to estimate cross-country growth regressions
where average annual growth in gross domestic product
(GDP) per capita over several decades is expressed as a
function of measures of schooling and a set of other variables
deemed important for economic growth.