(a) SF-corrected radio luminosity versus black-hole mass (as in Fig. 6a). Overplotted lines show L_1.4 ∝ M_BH (dashed) and $L_{1.4}\propto M_{\mathrm{BH}}^{1/2}$ (dotted line); see Eq. (4). (b) Radio luminosity as a function of bolometric luminosity (as in Fig. 6d). Overplotted lines show L_1.4 ∝ L_bol² (filled), L_1.4 ∝ L_bol (dashed), and L_1.4 ∝ L_bol^1/2 (dotted line); see Eq. (4). (c) Radio loudness versus Eddington ratio (as in Fig. 5c). Overplotted dashed lines show, for three arbitrary normalizations, $\mathcal{R}\propto {\lambda }^{-1/2}$ up to a critical Eddington ratio of λ = 10⁻², above which ℛ remains constant (see Eq. (5)). All panels show radio Seyferts, OPARGs, and OPIRGs (sample sizes in legends). Lines are labelled with their respective scaling relation exponents.