Purity and completeness as a function of redshift for groups identified in a flux-limited sample in redshift space. The left box shows the purity while the right box shows the completeness when an LF varying with redshift and V₀ = 130(1 + z) km s^-1 is used to compute the linking length parameters. In the left box (purity), the top panels show the fraction of galaxies identified that can be associated with galaxies of the group with the highest matching rate in the corresponding control sample (solid lines), and the fraction of galaxies that are classified as interlopers (dashed lines). In the right box (completeness), the top panels show the fraction of galaxies in the control sample that can be associated with galaxies identified in the spectroscopic group with the highest matching rate (solid lines), and the fraction of galaxies from the control sample that are classified as missing (dashed lines). The bottom panels show the trends observed for the fraction of groups within the six categories of purity or completeness (see text for description). The short-dashed magenta lines correspond to the complement of P6 and C6.