LIGO Detector Characterization in the Second and Third Observing Runs

The characterization of noise sources and instrumental artifacts of the Advanced LIGO detectors in the second and third observing runs has increased the sensitivity of the instruments, allowing for a higher number of detectable gravitational-wave signals, and provided confirmation of all observed gravitational-wave events. In this talk, I outline how LIGO data differs from the output of an idealized interferometer and how these differences impact searches for and analyses of gravitational-wave signals. I present the methods used to characterize the LIGO detectors and how this information is incorporated into LIGO-Virgo analyses in the second and third observing runs. I detail how inclusion of data quality information has improved analyses of gravitational-waves from both transient and persistent sources.