Jean Marie McGloin is an Associate Professor in the Department of Criminology and Criminal Justice at the University of Maryland. She received her Ph.D. from the School of Criminal Justice at Rutgers University-Newark in 2004. Her research primarily focuses on groups and crime and offending specialization. Her recent publications have appeared in Criminology, the Journal of Research in Crime and Delinquency, and the Journal of Quantitative Criminology. Christopher J. Sullivan is an Assistant Professor in the School of Criminal Justice at the University of Cincinnati. He received a doctorate from Rutgers University's School of Criminal Justice in 2005. His research interests include developmental criminology; juvenile delinquency and prevention policy; and research methodology and analytic methods. His recent work has appeared in Criminology, Prevention Science, Journal of Research in Crime and Delinquency, Journal of Youth and Adolescence, Journal of Quantitative Criminology, and Criminal Justice and Behavior. Leslie W. Kennedy is University Professor of Criminal Justice at Rutgers University -Newark. He is also the Director of the Rutgers Center on Public Security. Dr. Kennedy's current research in public security builds upon his previous research in event analysis and understanding the social contexts in which hazards to society are identified and deterred.