We show the cumulative probability distribution of the EW([O iii])/EW(Fe ii) equivalent-width ratio for three samples: our sample of radio-selected BAL quasars (bold solid line); 17 low-redshift RL objects from the BQS (Boroson & Green 1992, dashed black line) and 4 low-redshift, radio-quiet BAL quasars from the BQS (dot–dashed grey line). Arrows indicate objects that have only limits on the ratio from non-detection of either [O iii] or Fe ii. The limits are quoted at 3σ confidence.