1step,rule,n_before,n_after,n_removed,rationale21_read,all data rows of firm_panel.csv,2140,2140,0,rows read (excluding header)32_drop_column_rating_2025,remove column rating_2025 (known only in 2025),2140,2140,0,"information-availability rule: value not known at end of year t; column removal, no rows removed"43_drop_exact_duplicates,drop rows that are exact copies of an earlier row (all columns),2140,2100,40,assembly error: duplicated firm-year records; identical in every field so one copy kept54_drop_unobserved_outcome,drop firm-years with default_next empty,2100,1800,300,outcome year not observed at the end-2022 data cut (origin years [2022]); outcomes not imputed65_drop_missing_predictors,drop rows with any missing predictor,1800,1800,0,complete-case requirement for OLS7