Justin Hummer is an associate behavioral and social scientist at the RAND corporation. As a clinical psychologist, Hummer has expertise in evidence-based psychological treatments for addictive behaviors and mental health in adolescents, young adults, and military populations. His research focuses on better understanding and treating problematic substance use, trauma, and other mental health concerns through ecological frameworks that emphasize relevant developmental, familial, social, and cultural contexts. Hummer has considerable background in the design and evaluation of mental health and substance use interventions delivered through digital platforms, with a focus on identifying important mechanisms of change. He continues to grow experience in military health services research, including ways to strengthen access to and quality of mental health care for veterans and active and reserve component service members. Hummer received his Ph.D. in clinical science from the University of Southern California and completed his predoctoral internship at the VA Sacramento Healthcare System.