school-age population relative to the adult population. Using aggregate cross-national data on age structure, school enrollments, and school expenditures, Schultz found no significant effect on school enrollment rates of the proportion of the population in school age. He also found no noticeable effect of relative cohort size on the shares of gross national product (GNP) allocated to education, although he did find a negative association between the proportion of the population of school age and public school expenditures per child. Kelley (2001) notes that several other studies based on cross-country data also suggest that there is no impact of relative cohort size on the share of national budgets allocated to schooling. Kelley (1996) updated Schultz’s analysis using data from the 1980s and continued to find no significant effect of cohort size on the share of educational spending in GNP, although he did not look directly at the impact on enrollment.
In the case of Brazil, several studies have mentioned the potential benefits generated by lower population growth rates and decreases in the relative and absolute size of the school-age population. Birdsall and Sabot (1996) point to Brazil’s rapid increase in the number of children of school age in the 1970s and 1980s as potential cause for the poor educational performance of the 1980s. Rigotti (2001) argues that the decline in the population pressure and resulting smaller cohorts of school-age groups may have helped the performance of the educational system. Along the same lines, Castro (1999) has pointed to the high proportions of the population of school age of north and northeast Brazil as one of the potential reasons for lower enrollment rates in these regions. Although past research has recognized the importance of cohort size on children’s schooling in developing countries, this research has typically relied on cross-national regressions using aggregate data. Our analysis will take a different approach, using a combination of time-series and cross-state variation in cohort size, and using household survey data that make it possible to look at the impact of household-level variables as well as aggregate variables.
In addition to the literature on cohort size, there is an even larger literature analyzing the impact of family size on schooling outcomes. As pointed out in the reviews by Lloyd (1994) and Kelley (1996), previous research in this area has produced mixed results, ranging from negative effects to statistically insignificant effects to positive effects. Most empirical studies on educational attainment in developing countries have found that children from large families attain less schooling on average than children with fewer siblings (Anh et al., 1998; Knodel and Wongsith, 1991; Marteleto, 2001; Parish and Willis, 1993; Patrinos and Psacharopoulos, 1997). This is often attributed to a dilution of resources, with a smaller share of financial and interpersonal resources allocated to each child in larger families. Some studies, however, have found a positive association between family size and education (Chernichovsky, 1985; Hossain, 1988; King et al., 1986; Mueller, 1984; Zajonc, 1976), a result that Kelley (1996) argues could be theoretically plau-