Comparison between LABOCA 870 μm and PdBI 1.3 mm fluxes for SMGs (indicated in the panel) detected (middle panel) and not detected (top panel) with the PdBI. For LABOCA sources identified as multiple PdBI sources the individual PdBI source fluxes were added, and for the LABOCA sources not detected by PdBI 1.3 mm flux estimates for the most likely multi-wavelength counterparts were extracted from the PdBI maps (see Sect. 3.3 for details). The bottom panel shows the comparison between AzTEC 1.1 mm and SMA 890 μm fluxes (adopted from Younger et al. 2007, 2009) for AzTEC/JCMT SMGs in our 1.1 mm-selected sample. The solid line in all panels shows the flux ratios for a spectral power law index of 3.