Comparison of photometric, mixed, and spectroscopic redshifts. Top panel: projected two-point correlation functions in the redshift range 0.1 < z < 0.5. Data points are the two-point correlation function estimate from CODEX clusters. The solid curve is the predicted dark matter two-point correlation function scaled by computed from the halo mass estimates. Bottom panel: relative difference between the measured and predicted two-point correlation functions. The data points have been shifted horizontally for clarity.