Presentation #115.21 in the session Multi-Messenger Astrophysics.
During the first three observing runs of the gravitational-wave detector network, ~100 compact binary mergers have been observed providing novel probes of astrophysics, cosmology, and relativity. For example, the masses and spins of black holes in merging binaries have the potential to teach us about the formation history of these objects. While many studies have attempted to extract this information from the observed sources, the analyses employed can incur significant systematic errors. In this talk, I will describe some recent results on black hole spins and how to ensure their robustness to analysis systematics.