Peer effects on teenage fertility: Social transmission mechanisms and policy recommendations

We present instrumental variable results suggesting that the likelihood of having a teenage pregnancy is influenced by peers. We show that the instruments (peer-level teen childbearing of mothers and the average age of menarche) are plausibly exogenous across cohorts of students attending the same school. The estimates are large—a 10 percentage point increase in peer pregnancies is associated with a 2–5 percentage point greater likelihood of own-pregnancy. Peer influence is greater in environments with other policy factors that also increase teenage pregnancy rates and may operate primarily through shaping social norms rather than information or knowledge-sharing mechanisms.