Stephen Mastrofski is University Professor Emeritus in the Department of Criminology, Law and Society at George Mason University. His research interests include police discretion, police organizations and their reform, and systematic field observation methods in criminology. His publications cover implementation and impact of community policing, Compstat, body cameras, proactive policing, and law enforcement CEOs as agents of change. Using systematic observation, his research has included police officer decision making and performance, arrest, search and seizure, use of force, procedural justice, and citizen compliance. In 2000 he received the O.W. Wilson Award from the Academy of Criminal Justice Sciences for education, research, and service on policing. In 2008 he and his coauthors received the Law and Society Association’s article. In 2010 he was elected a Fellow of the American Society of Criminology. He received the 2015 Lifetime Achievement Award from the Division of Policing of the American Society of Criminology.