Oh Brother, Where Start Thou? Sibling Spillovers on College and Major Choice in Four Countries

Authors: Adam Altmejd, Andres Barrios Fernandez, Marin Drlje, Joshua Goodman, Michael Hurwitz, Dejan Kovac, Christine Mulhern, Christopher Neilson, & Jonathan Smith 

Project Summary

A group of international collaborators, including Adam Altmejd, Andres Barrios-Fernandez, Marin Drlje, Joshua Goodman, Michael Hurwitz, Dejan Kovac, Christine Mulhern, Christopher Neilson, and Jonathan Smith, worked to identify the causal effect of one particular social connection: an older sibling who attends college. Using data from administrative records in Chile, Croatia, Sweden, and the United States, the research team investigated whether a student’s choice of college and major is affected by the college enrollment of an older brother or sister.

Key Findings

An older sibling’s acceptance into their target college and major increases the likelihood that a younger sibling will enroll in the same college or major. Additionally, in the United States, an older sibling’s enrollment in a 4-year college causes the younger sibling to be more likely to attend a 4-year college at all. These effects persist for siblings who are more than 5 years apart in age and are present regardless of the gender match of the siblings. Effects are strongest among students who are statistically least likely to go to college, based on family income, parental education, and other characteristics. These effects are also more potent when the older sibling is accepted to a relatively high-quality college, as measured by the average qualifications of peers and the school’s dropout rate.

Implications and Recommendations

The findings constitute some of the earliest evidence that social networks have a meaningful impact on college decisions. The interpretation best supported by the findings is that older siblings affect their younger siblings’ college choices through the dissemination of subtle information about the college experience—information that would be difficult or impossible to obtain otherwise. Sibling effects strongly impact students who have the least exposure to college. Policymakers could seek to mimic these sibling spillovers effects for students who are least likely to go to college by creating in-depth mentorship programs that connect prospective students with current college students or alumni from similar communities.

college students studying

Project Resources