A comparison of the various redshift methods used in this work. For the top plot, photometric versus spectroscopic, we have highlighted in red sources AzTEC/C61 and C8a which have ambiguous photometric redshifts. Source C61 also has a synthetic redshift, which we have plotted as an open red circle. The large negative error bar for the photometric redshift of AzTEC/C61 has been suppressed for clarity. In the bottom plot, FIR versus spectroscopic, we have noted AzTEC/C113 and AzTEC/C45 which, despite meeting our criteria for being part of the training set, proved to be significant outliers and were therefore ultimately ignored in our z versus λ_peak fit. The dashed line in each panel indicates a 1:1 redshift match.