Penn World Tables 9.0
See this document, which reviews the academic debate on the quality of Barro-Lee dataset.
A well-known dataset on average years of schooling (i.e. stock of human capital).
The 2010 updated version is now available at www.barrolee.com.
For details on the data construction, read Robert J. Barro and Jong-Wha Lee, "International Data on Educational Attainment: Updates and Implications" (CID Working Paper No. 42, April 2000). This 2000 paper is an updated version of Barro and Lee (1993). Both papers compare various measures of human capital.
The average years of schooling is available for the six sets of the population: male over 25, female over 25, all over 25, male over 15, female over 15, all over 15.
Population over the age of 15 "corresponds better to the labor force for many developing countries." (Barro and Lee 2000, p.2)
Percentages of those who attained/completed each level of school in the total/male/female population are also available. Note that the sum of variables LU, LP, LS, and LH is 100; Lx-LxC, where x is either P, S, or H, is the percentage of those dropping out before completing primary, secondary, or higher school, respectively. In other words, the percentage of ".... school attained" contains the percentage of "... school complete".
Downloadable at this page by Center for International Development at Harvard University (CID).
The data file in the panel dataset format is best avoided because it excludes countries not in Penn World Table 5.0 (e.g. former socialist countries).
Note that variable SHCODE (numerical country code in Penn World Table 5.0) is different from the one in Penn World Table 5.6.
A very minor point, but the data entries for USSR/Russia in 1990 seem unreliable. Population seems to refer to USSR while educational attainment figures seem to refer to Russia.
Papers using this dataset include Acemoglu et al. (2005) and Glaeser et al. (2007).
For other datasets on average schooling years, see Kyriacou (1991), which is used by Benhabib and Spiegel (1994, JME), and Nehru et al. (1995), which is used by Pritchett (2000).
See Krueger and Lindahl (2001, JEL) for critical reviews on average schooling year data.