In many households, the oldest sister is one of the first family members to acquire any schooling, making her an important source of help with studies at home. Surveys show that only one out of five children who receive help with studies from a family member get it from a parent. When parents are not the ones helping with studies, the oldest sister fulfils that role 70% of the time. Given the low education of parents, and the oldest sister’s role as a childcare provider and tutor, one might expect oldest sister’s schooling to meaningfully impact younger sibling learning and development.

This is from research into the benefits of educated older sisters in Pakistan. Specifically in rural areas, where three quarters of mothers and two fifths of fathers were uneducated.

Javaeria Qureshi from the University of Illinois found that having an educated older sister increased a primary-aged brother’s years of schooling, ability to read and write, and add and count.

These oldest sisters’ schooling effects are the same order of magnitude as those for maternal schooling. Interestingly, increasing the oldest sister’s schooling has no impact on older brothers’ educational outcomes, indicating that the younger brothers are not benefitting merely from being around more educated family members or because their parents are increasing investments in all of their children’s education. Instead, the results suggest that younger brothers’ education improves because they have a more educated childcare provider, tutor and role model in their oldest sister. 

This is an important finding not only due to the number of children not being educated in Pakistan, but the gendered nature of education in many countries.

Women are often presumed to have a lower return on education due to a lesser propensity to work and support parents later etc. This can be especially important in resource constrained families even if there isn’t a prejudice against educating girls.

But as is so common, there’s stuff we haven’t or couldn’t measure, the world is complicated and factors interrelated. Beyond the individual benefit of educating a girl, it appears to be positive sum for the family.

As always my emphasis.