FIRST GENERATION ESTIMATES Economists have developed different techniques for estimating rates of return to education, and it is instructive to see how methodological advances have replaced earlier approaches and dealt with problems of identification. Some of the first studies have been compiled in meta-analyses by World Bank economists George Psacharo poulos and Harry Patrinos. Table 8-3 is from their work and includes calculations of internal rates-of-return for over 75 nations. Some of these studies refer to outcomes as far back as the late 1950s, whereas others refer to the 1990s. Rates of return esti- mated for individual countries are averaged together and presented as a mean value for different income categories and regions. These are simple cross-country averages and are not weighted by population size. They are real not nominal rates of return because they are based on cross-sectional estimates that measure earnings in the same current dollars. A number of patterns can be observed in these data. Returns on all levels of schooling and in all income categories are almost always in double digits. Returns