Absolute error of the true-z distribution estimated using samples processed by setting the negative measurements to a tiny positive value (empty markers) or not (filled markers). Shown are the results from SC (orange), CZ (red), and SC+CZ (blue). Upper panel: ${\displaystyle \sum _i}|{\widehat{P}}_{ij\prime }-P_{ij\prime }^{\mathrm{true}}|$, the absolute difference between the true-z distribution measured from the mock, P_ij′^true and the one estimated, ${\widehat{P}}_{ij\prime }$. Lower panel: ${\displaystyle \sum _i}|{\widehat{P}}_{ij\prime }-P_{ij\prime }^{\mathrm{true}}|/{\sigma }_{P_{ij\prime }}$ the absolute difference normalized by the estimated error σ_Pij′.