Fraction of small (major axis < 10″) radio sources with a likelihood ratio match as a function of the S/N (S_I/σ_SI). The colour of the points corresponds to the number of sources in each S/N bin. The blue horizontal line corresponds to the overall LR identification rate obtained. We find that lowering the detection threshold to a peak detection significance of 4σ_thresh results in a large fraction (∼30%) of additional, genuine radio sources compared to adopting a 5σ_thresh threshold. However, this also leads to a small increase in false detections (by ∼2–3%).