Flowchart detailing our sample selection. Retired galaxies are galaxies that have stopped forming stars and are ionized by their populations of HOLMES (see: Stasińska et al. 2008). Similarly to the star-forming galaxies, they are not relevant for the present study. The parent ‘ROGUE I & II SDSS MGS’ sample already incorporates redshift range limits, optical spectral quality cuts, and removal of sources whose radio morphology is blended or non-detected. The number of sources in each subsample is given in the panels. Numbers in brackets show number counts before applying limits to the S/N of [O III] or W3 luminosities, to emission line detection, and to the star-formation-corrected radio luminosity values.