Comparison of Bayes factors between soft excess models. The Bayes factor for the double power law is shown on the horizontal axis, while the Bayes factor for the blackbody model is shown on the vertical axis. The dashed grey line shows the one-to-one relation, with sources lying below the line being better fit with the PL+PL model, and sources above the line being better fit with the PL+BB model. Sources which show evidence for a soft excess (K_pl > 2.586, corresponding to a 97.5% significance) are shown in black, and sources which do not show evidence for a soft excess are shown in grey.