Red: our fiducial analysis makes best use of the spectroscopic coverage of GOGREEN. It reduces the effect of cosmic variance because it does not rely on the statistical subtraction of interlopers from a reference field. However, for this approach we have to assume that the spectroscopic subset is representative of the full galaxy population. Black: an alternative approach is to subtract the fore- and background interlopers statistically by making use of the external COSMOS/UltraVISTA survey. The latter approach does not make use of the spectroscopy at all, yet presents results that are fully consistent with those obtained with the fiducial method. Small horizontal offsets have been applied, to the data points only, for better visibility.