Distributions for the difference between the observed ALMA 870 μm flux densities and the predicted 870 μm flux densities from CIGALE using an error expansion factor of 2 (panel a), 3 (panel b), and 4 (panel c) in XID+. The Gaussian distribution for each expansion factor is also shown in orange, along with the means (μ) and standard deviations (σ) of the distributions. All the distributions have an approximately consistent σ so the best expansion factor was deemed to be that with μ closest to zero: 2 times the error from CIGALE.