Bayes factors for a GW signal from an individual circular SMBHB as a function of GW frequency in the NANOGrav 11 yr data set. We found no strong evidence for GWs in our data. The highest Bayes factor was at ﹩{f}_{\mathrm{gw}}=109\,\mathrm{nHz}﹩, for which ﹩{{ \mathcal B }}_{10}=15(6)﹩. For all other frequencies searched, the Bayes factors were close to 1.