The spectroscopic success rate (SSR) quantifies the fraction of targets for which the redshift could be measured with >95% confidence. On the left we show the mean SSR of each pointing divided by quadrant (7 × 8 arcmin). The inset histogram gives the cumulative number of quadrants with SSR below the given value. On the right, we show the SSR as a function of i_AB magnitude (solid curves) with an analytic fit (dashed curves). The sample is divided based on the overall quality of the quadrants quantified by SSR. The quadrants are ranked by mean SSR and the curves are computed for each decile. The range of SSR and the number of sources in the bin are given in the figure legend.