  This paper uses a "principal strata" approach to decompose treatment effects
and interpret why a schooling intervention that yielded exceptional initial
effects yielded substantially smaller effects in a replication years later. The
specific application is a set of 2008 and 2015 replications of an intervention
aiming to increase primary education for girls in rural Afghanistan. The
intervention offers a new schooling option, and as such, its effects depend on
how individuals use alternatives that already exist. The principal strata
approach accounts variation in use patterns when comparing effects across the
replications. Our findings show that even though the share of girls for whom
the intervention would be valuable dropped considerably in 2015 as compared to
2008, the intervention was even more efficaciousness for those who continued to
benefit from it.
