Cumulative distributions of the FWHMs (in the units of km s⁻¹) of the wing component of the [O III]λ5007 emission line for the red and control QSOs. Two cuts were required from our parent sample due to observability of the [O III] line (z < 1) and to avoid contamination from the host galaxy (log L_6 μm > 44.5). Left panel: entire population, without any further quality requirement. Right panel: we restrict our study to high quality detections of the wing components, based on a SNR criterion defined in the plot, which is consistent with our visual inspection of the lines. The high-quality detection cut increases the evidence for a prevalence of high velocity winds in red QSOs as compared to control QSOs.