FIRST-detected fraction as a function of redshift for the two different subsamples of our new catalog: The red quasars (rQSO) shown in dark red, and the red quasars within the AGN wedge (AGN-w rQSO) shown in orange. The luminosity–redshift matched blue quasars from SDSS are also included. The area highlighted by blue diagonal stripes corresponds to their detection fraction ±1σ confidence intervals. The shaded purple area highlights the area corresponding to the blue SDSS quasars matched with redshift–luminosity to our red quasars within the AGN wedge. The two dashed lines show the median of the luminosity–redshift matched blue quasars from SDSS and the blue SDSS quasars matched with redshift–luminosity to our red quasars within the AGN wedge.