step,rule,n_before,n_after,n_removed,rationale
raw,all rows read,417,417,0,input
1,drop months before 1992-03 (no lags / neworder_chg missing),417,415,2,task-specified training start; features need ip lags and neworder_chg
2,drop months s with s+1 > last origin 2026-08 (target not available at last origin),415,413,2,information rule: s+1 <= t at the last origin