1step,rule,n_before,n_after,n_removed,rationale21,drop rows with any missing value,1000,1000,0,outcome/treatment/cluster id required32,drop duplicate student_id,1000,1000,0,one row per student43,treated must be 0/1,1000,1000,0,binary assignment54,treated constant within school,1000,1000,0,school-level assignment6