Star formation rates, SFR, (left), specific SFRs, sSFR, (right), for the DGS (crosses) and KINGFISH samples as a function of metallicity, colour coded with M_star (colour legend in right panel). For the KINGFISH sample, we distinguish the sources that have been classified as “star-forming” (SF, downward triangles) or as “AGN” (stars) by Kennicutt et al. (2011). The distribution of each parameter is indicated on the side of each panel for both samples: solid line for DGS and dashed line for KINGFISH.