A Comment on "Friendship and female education: Evidence from a field experiment in Bangladeshi primary schools" by Hahn et al.
Hahn et al. (2020), published in the Economic Journal, evaluate a treatment randomized across 115 Bangladeshi primary schools that assigned students to study for one week either in groups of friends or with randomly picked peers. They find that the friends treatment improves math performance, but only among low-ability girls. We identify four sets of unresolved discrepancies: inconsistent accounts of implementation responsibilities, irregularities in the sample and group structure, misalignments between reported procedures and observed data, and implausible missing-data and attendance patterns. Taken together, these issues are not merely reporting imperfections, but reveal multiple discrepancies between the published record, earlier versions of the study, the replication data, and the two replies subsequently provided by the authors. These unresolved discrepancies preclude independent verification of material aspects of the study record and raise serious concerns about the credibility of the reported findings.