A comparison of the distributions of left: C iv velocity relative to the SDSS-derived systemic velocity of the QSO, middle: C iv velocity relative to the Mg ii velocity, and right: black hole mass, contrasting the sub-mm detected QSOs (solid lines) and sub-mm non-detected QSOs (dashed lines) from the samples of Priddey et al. (2003a) and Omont et al. (2003). The histograms have been shifted slightly in the x-axis for legibility. Values used are from the compilation of Shen et al. (2011) except for the inclusion of the 10 Hα-based black hole masses presented in this work. In contrast to Shen et al. (2011) we use positive velocities to indicate redshift.