Ratios of SFRs determined from L_TIR to those determined by [OII] emission for the average galaxies of the three L_TIR subsamples plotted against L_TIR. In the Herschel subsamples, [OII] emission underestimates the true SFR by a factor of ~40−80. Increasing L_TIR results in an increase in the SFR(L_TIR)/SFR([OII]) ratio, presumably a consequence of the larger dust content in the average high-L_TIR galaxy relative to its lower luminosity counterpart. Only random errors are used resulting in error bars the sizes of the symbols. Systematic errors related to SFR conversions and extinction are quite large, but are unnecessary to include here as the comparison is relative and any systematic offset would affect each ratio in the same manner. The SFR(L_TIR)/SFR([OII]) ratio is used to determine the nebular extinction, E(B − V), for the average galaxy in each subsample. These values are given at the top of the plot along with the definitions of each subsample.