Spectroscopic completeness of our main sample. The magenta dashed line denotes the spectroscopic completeness as a function of yps1-band magnitude. The histogram is divided into several components filled by different colors and represents newly identified high-redshift quasars (orange), nonquasars (blue), and unobserved candidates (gray). The black dotted line represents yps1 = 21.0 mag, which we treat as our quasar survey flux limit.