Thompson's research focuses on the role of law enforcement agency policies and practices in shaping use of force decisions. The goal of this research is to evaluate law enforcement agency policies for their effect on rates of fatal and non-fatal use of force. Additionally, Thompson's research offers an evaluation of state efforts to catalog and circulate data on police use of force. Overarching themes in Thompson's writings include regulation, supervision, and discretion; crime and violence; and state collected data. Thompson has partnered with the University of California Firearm Research Center to begin statewide efforts to better understand firearm violence.