Percentage difference in the errors on the final parameters among CosmicFish, CosmoSIS, STAFF, and TotallySAF for the GC_ph+WL+XC combination (top panels) and the GC_s+GC_ph+WL+XC combination (bottom panels). We assume here a flat (w₀, w_a) cosmology. This comparison is done both in the pessimistic and optimistic configurations (left and right panels, respectively); we note, however, that for the top panels, since no spectroscopic galaxy clustering is included, there is no need to perform a cut in z (as the pessimistic setting would require). The light grey band correspond to the marginal errors on the parameters, while the dark grey band indicates the errors when we do not marginalise over the other parameters.