Things that might go bump in the night: Assessing structure in the binary black hole mass spectrum

Several bumps and dips in the mass spectrum of merging binary black holes have been identified in the LIGO/Virgo data. But are these features signatures of the astrophysical process that produced the observed binary black holes, or are they just due to statistical fluctuations? I will present an analysis addressing this question, and will discuss the implications of these results for the formation of merging black holes, the possible underlying morphology of the binary black hole mass spectrum, and what parts of this spectrum we can expect to resolve with detections in LIGO/Virgo/KAGRA's upcoming fourth observing run.