Education may also affect per capita income growth via its impact on the
denominator, i.e. population growth. For example, a study of 14 African countries in the
mid-1980s showed a negative correlation between female schooling and fertility in
almost all countries, with primary education having a negative impact in about half the
countries and no significant effects in the other half, while secondary education
invariably reduced fertility (Birdsall, Ross and Sabot, 1995); (Jayaraman, 1995); (Strauss
and Thomas, 1995); (Thomas, Strauss and Henriques, 1991); (Behrman and Wolfe,
1987a).