Many observers have emphasized the crucial importance of human capital, particularly as attained through education, to economic progress (Lucas, 1988, Barro, 1991 and Mankiw, Romer and Weil, 1992). An abundance of well-educated people goes along with a high level of labor productivity. It also implies larger numbers of more skilled workers and greater ability to absorb advanced technology from developed countries. The level and distribution of educational attainment also have impact on social outcomes, such as child mortality, fertility, education of children, and income distribution.

There have been a number of attempts to measure educational attainment across countries to quantify the relationship between it and economic and social outcome variables. Earlier empirical studies used school enrollment ratios or literacy rates. But although widely available, these data do not adequately measure the aggregate stock of human capital available contemporaneously as an input to production.

Earlier versions of the Barro-Lee Data Set (1993, 1996, and 2001) filled this data gap by constructing measures of educational attainment for a broad group of countries.

The earlier versions employed perpetual inventory method using census/survey observations on the educational attainment of the adult population group over age 15 or over age 25 as benchmark stocks and new school entrants as flows that added to the stocks with an appropriate time lag. The flow estimates were estimated using information on school-enrollment ratios and population structure over time.

As new data becomes available, the data set is updated and expanded. Barro-Lee (1993) provides educational attainment estimates for 129 countries for 1960–1985. This new Data Set provides complete estimates for 146 countries for the period 1950-2010.