Quasar luminosity function measurements (black circles) compared to the C09 data (blue open circles at 0.68 < z < 2.6). The blue dashed curve is the LF of C09 and the best-fit model of this analysis is shown as the red curve. The green curves are best fits to COSMOS data (Masters et al. 2012) at z ~ 3.2 (plain curve) and z ~ 4.0 (dashed curve). The cyan line is the best fit, with fixed-α, to binned LF data from SWIRE and SDSS at z ~ 3.2 (Siana et al. 2008).