1step,rule,n_before,n_after,n_removed,rationale21,"candidate model forecast-actual pairs: 10 origins x 2 horizons; drop pairs whose target month is missing from first_release.csv",20,20,0,"all 20 targets (2025-09..2026-09) present in first_release.csv"32,"drop pairs with non-finite forecast or actual",20,20,0,"no missing values in vintages or first_release"4