1step,rule,n_before,n_after,n_removed,rationale21_drop_exact_duplicates,drop rows identical to an earlier row on all columns,445,400,45,assembly error: same firm record appended more than once32_convert_units,revenue_musd = revenue/1000 if unit==USD_thousands else revenue,400,400,0,recoding only; 60 firms reported in USD thousands43_drop_missing_revenue,drop firms with empty revenue,400,394,6,revenue unknown; cannot enter revenue aggregates (still counted in mean_employees)5