1step,rule,n_before,n_after,n_removed,rationale2drop_unavailable,"target month tau+1 <= 2026-02-01, y(tau-2) and e(tau-1) observed",345,335,10,information-availability rule / series edges3exclude_covid,drop rows whose target/predictor months fall in 2020-03..2021-12,335,310,25,COVID outliers dominate OLS; decided with pre-2022 info4