Background: Extended kin networks are an important social and economic resource in Africa. Existing research has focused primarily on intergenerational ties, but much less is known about "lateral" ties, such as those between siblings. In contexts of high adult mortality (i.e., fewer parents and grandparents) sibling interdependencies may assume heightened importance, especially during the transition to adulthood.

Objective: In this paper, we extend the resource dilution perspective that dominates research on sibling relationships in early childhood and propose an alternate framework in which siblings represent a source of economic support that contributes positively to educational outcomes at later stages of the life course.

Methods: We draw upon longitudinal data from young adults (age 15-18) in southern Malawi to assess the scope and magnitude of economic transfers among sibship sets. We then explore the relationships between sibship size, net economic transfers between siblings, and four measures of educational progress.

Results: First, exchanges of economic support between siblings are pervasive in the Malawian context and patterned, especially by birth order. Second, economic support from siblings is positively associated with educational attainment, as well as with the odds of being at grade level in school, both contemporaneously and prospectively.

Conclusions: During young-adulthood, economic support from siblings acts as a buffer against the negative association between sibship size and schooling outcomes that has been documented at earlier ages.

Comments: We question the established notion that siblings unilaterally subtract from resource pools, and argue that sibling support may be consequential for a wide range of demographic outcomes in a variety of cultural contexts. Our findings point to the need for additional research on the importance of lateral kinship ties across cultural settings and throughout the life course.