removed school fees in grades one through ten throughout Ethiopia, the local magnitude of the reform’s impact depends on pre-reform levels of education in each part of the country. This concept is similar to that underlying the strategy of Bleakley (2010) and Lucas (2010, 2013), which used pre-eradication levels of malaria to identify local variation in the impact of eradication programs; Lucas and Mbiti (2012a,b) applied the same concept more directly to the post-2000 removal of school fees in Kenya. A similar differencein-differences identification strategy can be applied to Ethiopia. Following the reform, ten years of fee-free schooling became available to every single student; however, prior to the reform, some portion of these grades were already being completed. In areas of the country where schooling levels were high before the reform’s implementation, the removal of school fees would have had only a small impact relative to regions where few students attended school in the pre-reform period. Across Ethiopia, this pre-reform level of schooling is evaluated for each of the 60 zones in the country.

In each zone, _z_ , the maximum potential magnitude of the reform, _Mz_ , is calculated using information on schooling of individuals from that zone born between 1966 and 1969.<sup>1</sup> Only data for women are used to calculate the measures described in this article. Women with birth dates between 1966 and 1969 were born significantly prior to the implementation of the reform, such that even if they entered primary school five years late and completed ten years of education, they would not have had access to any free schooling. In each zone, some fraction of the population, _Fz,_ 0, never enters school; in other words, they complete zero years of schooling. For this subset of the population, the reform has the potential to increase schooling by ten years. An additional portion of the population, _Fz,_ 1, dropped out after completing one year of schooling; this subset of the population could gain as many as nine years of additional schooling, and so on. The maximum potential magnitude of the reform in zone _z_ is then calculated as the product of the number of potential additional years of schooling and the fraction of the population that dropped out after each grade, Equation (1) represents the number of free years of schooling made available by the reform in each zone, beyond what was being completed prior to the reform’s implementation. For students who make the decision to enter school following the reform’s implementation, the reform can directly increase schooling for them by as much as _Mz_ , relative to the pre-reform level of schooling in their zone. This maximum magnitude of the reform applies to all individuals entering school in 1995 or later, or, if starting school on time at age seven, cohorts born no earlier than 1987. Cohorts born in each successive year prior to 1987 benefited from one

> 1These data are from the 1994 Ethiopian census, collected by the Ethiopian Central Statistical Agency and made available as part of the Integrated Public Use Microdata Series (IPUMS) International by the Minnesota Population Center and the Ethiopian Central Statistical Agency (2017).

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