Searching for structure in the binary black hole spin distribution

The Advanced LIGO/Virgo interferometers have observed ∼70 binary black hole mergers. One of the key observables that can reveal the formation history of these binaries is the distribution of spin orientations. We show that when using more flexible models for the spin orientation, we find results that depend on the specific functional form chosen. We additionally highlight a failure model of population analyses using the observed gravitational-wave transient catalog.