Comparison of black hole mass (M_BH) estimates (left panel) and bolometric luminosity (L_bol) estimates (right panel) for a set of QSOs that have at least two spectra from different datasets. The estimate from the primary dataset is plotted on the x-axis and the estimate from the secondary dataset is plotted on the y-axis, where the hierarchy is based on preferences outlined in Sect. 4. The color of the solid core circle identifies the primary dataset, which is either SDSS (blue), zCOSMOS-Deep (purple), or zCOSMOS-Bright (red). The color of the outer circle identifies the secondary dataset, which may be zCOSMOS-Bright (red) or IMACS (green). The L_bol estimates, derived from direct measurements of the local continuum from the spectra, are very consistent between datasets. The M_BH estimates show more scatter and a small systematic variation about the 1:1 line.