Previous causal inference literature often required no interference among units,that is,the potential outcomes of a unit do not depend on the treatments of other units.This no-interference assumption,however,becomes unreasonable when units are partitioned into groups and they interact with other units within groups.In a motivating education example from Peking University,there are two types of students admitted through the college entrance exam(also known as Gaokao)or through recommendation(often based on Olympiads in various subjects).