The 20th century became a century of human capital thanks to its contribution to economic growth. However, such a contribution in extensive way is no more possible and the quality of education starts to play more important role. The aim of the paper is to create an indicator of educational quality from three different subjects of PISA tests. Thanks to such indicator the performance of 51 countries is computed. Furthermore, the intertemporal analysis suggests the overall convergence of countries and the backward shifts of the frontier between years 2006 and 2015. The last result suggests, that there exists strong relationship between the quality of education, calculated by DEA model and income per capita of the countries.