Redshift purity and sample completeness as a function of spectroscopic reliability threshold. The solid blue, dashed red, dotted green, and dash-dotted orange lines respectively correspond to a selection using only SPE reliability, SPE reliability combined with a photometric classification based on Euclid data, with the classification that uses Euclid and ground-based photometry, with the H_E magnitude limit selection, and with the colour selection in the (I_E − H_E)-H_E plane. In all cases the recall of the photometric classification is set to 95%.