Better Off On Their Own? How Peer Effects Determine International Patterns of the Mathematics Gender Achievement Gap

This paper applies recent spatial regression techniques in peer effects estimation to a sample of33coun-tries in the IAE’s TIMSS 2015 study in order to quantify the gender achievement gap in eighth grademathematics. Based on an education production function setting and controlling for the mediating influ-ences of student-, parent-, teacher-, and school-level factors, a significant, but small gender achievementgap amounting to10%of a country-level standard deviation is confirmed in the standard linear model.I model endogenous and exogenous peer effects based on the workhorse linear-in-means model as well ason homophily-based dyadic relations between students, both with controls for group unobservables. Theresults show that the effect size increases to12-14%, depending on the underlying socio-matrix. How-ever, the partitioned impacts suggest even larger effects when considering spillovers within the classroom.These could amount to as much as38%of a standard deviation, depending on the underlying dyadic peerweights, with the linear-in-means model possibly overstating the magnitude of classroom externalities.