The Halpern-Felsher lab studies developmental, cognitive, psychosocial and cultural/social factors involved in adolescents’ and young adults’ health-related decision-making, perceptions of risk and vulnerability, health communication and risk behavior. Our work particularly focuses on understanding and reducing adolescent and young adult substance use (including tobacco, electronic cigarettes, alcohol, and marijuana), risky sexual behavior, and risky driving. Our research uses a number of methodological approaches, including large-scale research projects, studies involving longitudinal data, online data collection methods, mixed qualitative and quantitative data, interview and focus group data, and survey data. We also develop, implement and evaluate interventions, including pre-post tests and randomized control trials. Our research spans several age groups, including children, adolescents, young adults and parents.