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Johns Hopkins Center for Gun Policy and Research

Faculty and Staff

Daniel Webster

Daniel Webster, ScD, MPH

Center Director

Daniel Webster is the inaugural Bloomberg Professor of American Health at the Johns Hopkins Bloomberg School of Public Health where he directs the Center for Gun Policy and Research and serves as co-lead of the Violence Prevention Workgroup of the Bloomberg American Health Initiative. Webster is one of the nation’s leading experts on the prevention of gun violence and has published over 120 articles in scientific journals on topics including gun policy, violence prevention, youth violence, intimate partner violence, suicide, and substance abuse. He is the lead editor and a contributor to Reducing Gun Violence in America: Informing Policy with Evidence and Analysis (Johns Hopkins University Press, 2013). Webster’s research has informed policies to reduce gun violence at the local, state, and federal level. He previously led Baltimore’s Homicide Review Commission and now leads the Johns Hopkins-Baltimore Collaborative for Violence Reduction. His awards include the American Public Health Association’s David Rall Award for science-based advocacy (2015), Baltimore City’s Health Equity Leadership Award (2016), Pioneer Award from the Injury Free Coalition for Kids (2017), and Johns Hopkins University Distinguished Alumni Award (2017).

Cassandra Crifasi

Cassandra Crifasi, PhD, MPH

Center Deputy Director
Assistant Professor

Cassandra Crifasi is an assistant professor of Health Policy and Management at the Johns Hopkins Bloomberg School of Public Health. Her primary research interests focus broadly on public safety including injury epidemiology and prevention, gun violence prevention and policy, attitudes and behaviors of gun owners, and underground gun markets. Crifasi teaches courses in research and evaluation methods and serves as Deputy Director of the Johns Hopkins-Baltimore Collaborative for Violence Reduction. She earned her PhD in Health Policy and Management from the Johns Hopkins Bloomberg School of Public Health in 2014 and an MPH in Environmental and Occupational Health from the Dornsife School of Public Health at Drexel University in 2010.

Jon Vernick

Jon Vernick, JD, MPH


Jon Vernick is a professor of Health Policy and Management at the Johns Hopkins Bloomberg School of Public Health. Vernick is the primary instructor for courses on issues in Injury and Violence Prevention, and Public Health and the Law. He is also Co-Director of the MPH/JD Program at Johns Hopkins Bloomberg School of Public Health. Vernick’s research has concentrated on ways in which the law and legal interventions can improve the public's health. He is particularly interested in epidemiological, policy, legal, and ethical issues associated with the prevention of firearm violence and other injuries. His firearm violence prevention work includes evaluations of state gun laws and scholarly analyses of gun policy. He was the primary author of an amicus brief on behalf of public health organizations in District of Columbia v. Heller, which was cited by Justice Breyer. He has published more than 100 scholarly articles and reports on firearms and other public health topics (including motor vehicle safety, tobacco policy, and preparedness). Vernick is committed to translating research findings into policy change, regularly working with legislators, media, courts, and advocates to provide information about effective policies. He earned his BA from Johns Hopkins University, a JD with honors from George Washington University, and an MPH from the Johns Hopkins Bloomberg School of Public Health.

Colleen Barry

Colleen Barry, PhD, MPP

Chair of the Department of Health Policy and Management
Fred and Julie Soper Professor

Colleen Barry is Chair of the Department of Health Policy and Management and a Fred and Julie Soper Professor with joint appointment in the Department of Mental Health at the Johns Hopkins Bloomberg School of Public Health. Barry's research focuses on how health and social policies can affect a range of outcomes for individuals with substance use disorders and mental illness, including access to medical care and social services, care quality, health care spending, financial protection and mortality. In addition, she conducts empirical research to understand how communication strategies influence public attitudes about addiction, mental illness and violence. A focus of this work is to identify evidence-based approaches to reducing stigma. She has led research studies funded by the NIH and various foundations including the Robert Wood Johnson Foundation, the Commonwealth Fund and the Arnold Foundation. She has authored over 160 peer-reviewed publications on a range of health policy and public health topics in journals such as the New England Journal of Medicine, Pediatrics, Health Affairs and the American Journal of Public Health. Barry is founding co-director of the Johns Hopkins Center for Mental Health and Addiction Policy Research. She is a core faculty member with the Johns Hopkins Center for Gun Policy and Research. She is Principal Investigator of the Johns Hopkins NIMH T32 Mental Health Services and Systems Training Grant. She serves on various national advisory boards on policy related to addiction, mental health and violence. She is currently a member of the National Academy of Medicine Consensus Panel on Medication Treatment for Opioid Use Disorder. Barry is also co-chair of the Forum on Mental Health and Substance Use Disorders of the National Academies of Sciences, Engineering, and Medicine.

Mark Dredze

Mark Dredze, PhD, MS

Associate Professor

Mark Dredze is the John C. Malone Associate Professor in Computer Science at the Johns Hopkins University, with affiliations in the Malone Center for Engineering in Healthcare, the Applied Physics Lab, the Human Language Technology Center of Excellence, the Center for Language and Speech Processing and the Center for Population Health Information Technology. He holds an appointment in Health Sciences Informatics in the School of Medicine. Dredze’s work explores new machine learning technologies for modeling language data. His work focuses on public health applications of these methods, such as discovering reasons for vaccine refusal, tracking developments in the tobacco control landscape, and measuring reactions to gun violence events. He earned his BS from Northwestern University, his MS from Yeshiva University and his PhD from the University of Pennsylvania.

Shannon Frattaroli

Shannon Frattaroli, PhD, MPH

Associate Professor

Shannon Frattaroli is an associate professor of Health Policy and Management at the Johns Hopkins Bloomberg School of Public Health where she serves as core faculty with the Center for Gun Policy and Research. Frattaroli teaches courses in Public Health Policy Formulation, Implementation Research and Practice, and Qualitative Research Methods. Her research focuses on policy and advocacy strategies designed to prevent injury and violence – particularly firearm-related domestic violence, with particular attention to how interventions are implemented once in place. Frattaroli is committed to efforts that advance the translation of research findings into policy and practice. Toward that end she is involved in the educational efforts and scholarship about Gun Violence Restraining Order laws that provide a process for temporarily dispossessing people of their firearms when they are exhibiting dangerous behaviors.

Sheldon Greenberg

Sheldon Greenberg, PhD


Sheldon Greenberg is a professor of Management and Leadership in the Johns Hopkins University School of Education and is the founding director of the Division of Public Safety Leadership. He served as Associate Dean in the School of Education for over 12 years. Greenberg developed and directed the Master of Science in Management and Master of Science in Intelligence Analysis and the Bachelor of Science in Management degree programs for public safety, which includes the Police Executive Leadership Program, U.S. Secret Service Executive Development Program, and U.S. Immigration and Customs Enforcement Executive Development Program. He served as associate director of the Police Executive Research Forum, a renowned law enforcement center for research. Greenberg began his career in the Howard County of Maryland Police Department, serving as a patrol officer, supervisor, and commander of the administrative services bureau. He served on several national commissions and is a member of the Federal Law Enforcement Training Accreditation Board. He is the author of three books and numerous articles.

Caitlin Hoffman, MPHCaitlin Hoffman Headshot

Director of Communications 

Caitlin Hoffman is a public health communications professional with over a decade of experience in program development, evaluation and communicating public health information to government officials, community stakeholders, healthcare professionals and the public. She leads the strategic communication program for the Department of Health Policy and Management, including the Center for Gun Policy and Research. She has conducted original research on health communication strategies and presented work at national conferences including the National Conference on Health Communication. Caitlin is passionate about translating evidence-based research into practice, using data to drive policy change, and emphasizing the importance of effective communication strategies. She comes to Hopkins after working for the Philadelphia Department of Public Health. Caitlin earned her BA from the Pennsylvania State University and an MPH from Emory University.

Katherine Hoops, MD, MPHKatherine Hoops Headshot

Assistant Professor

Katherine Hoops is an assistant professor of Pediatric Critical Care Medicine at the Johns Hopkins University School of Medicine. Her areas of clinical expertise are in pediatric sepsis and pediatric trauma. Dr. Hoops completed her residency training in pediatrics at the University of Alabama Birmingham before coming to the Johns Hopkins University School of Medicine to complete her fellowship in pediatric critical care medicine. Her research is focused on the prevention of pediatric gun injury. She conducts research on understanding messaging to patients and families on guns and improving physicians’ counseling on firearm safety. She is also involved in innovative quality improvement initiatives studying the use technology to improve care of critically ill patients and has been named as a Hexcite Fellow with the Johns Hopkins Technology Innovation Center. Hoops received her undergraduate degree from Florida State University, her medical degree at the University of Miami Miller School of Medicine in Miami, and her Master of Public Health in Health Policy and Management at the Johns Hopkins Bloomberg School of Public Health.

Alex McCourt, JD, PhD, MPHAlex McCourt Headshot

Director of Legal Research

Alex McCourt is an assistant scientist of Health Policy and Management at the Johns Hopkins Bloomberg School of Public Health. He is affiliated with the Center for Gun Policy and Research and the Center for Law and the Public’s Health. Trained as a public health lawyer, he combines legal research with empirical methods to study instances in which law plays a role in shaping the public’s health. Much of his work has focused on firearm policy and violence, including homicide, suicide, and intimate partner violence. He received his PhD from the Johns Hopkins Bloomberg School of Public Health and his JD/MPH from the University of Arizona.

Beth McGinty

Beth McGinty, PhD, MS

Associate Professor

Beth McGinty is an associate professor in the Departments of Health Policy and Management and Mental Health at Johns Hopkins Bloomberg School of Public Health. In addition to being a core member of the Center for Gun Policy and Research, she serves as a co-deputy director of the Center for Mental Health and Addiction Policy Research. Her research focuses on issues at the intersection of mental illness, substance use, and gun violence, including firearm suicide. At the Center for Gun Policy and Research, McGinty uses public opinion surveys and message framing experiments to assess public support for gun violence prevention policies. McGinty has conducted multiple analyses of news media coverage of gun violence and mental illness, as well as national public opinion surveys to assess Americans’ views about firearm policy and practices. She received her PhD in Health Policy and Management in 2013 from the Johns Hopkins Bloomberg School of Public Health where she was a Sommer Scholar and received an MS in Health and Behavior Studies from Columbia University in 2006.

Paul S. Nestadt

Paul S. Nestadt, MD

Assistant Professor

Paul Nestadt is an assistant professor jointly appointed in the Department of Psychiatry at the Johns Hopkins School of Medicine and the Department of Mental Health at the Johns Hopkins Bloomberg School of Public Health. He completed medical school at New York Medical College, psychiatric residency at the Johns Hopkins Hospital, and a postdoctoral fellowship in the Psychiatric Epidemiology Training Program at the Johns Hopkins Bloomberg School of Public Health. Nestadt’s research interests include the epidemiology of suicide and the role of firearm access in predicting death. His suicide research also includes opioid-related suicidality and the limitations of clinical screening for dangerousness. Nestadt serves as the supervising psychiatrist for the Johns Hopkins Anxiety Disorders Clinic and as attending psychiatrist in the Motivated Behaviors Unit.

Elizabeth Stuart HeadshotElizabeth A. Stuart, PhD

Associate Dean for Education

Elizabeth A. Stuart is Professor in the Department of Mental Health at the Johns Hopkins Bloomberg School of Public Health, with joint appointments in the Department of Biostatistics and the Department of Health Policy and Management, and Associate Dean for Education at JHSPH. She received her PhD in statistics in 2004 from Harvard University and worked at Mathematica Policy Research from 2004 to 2006.  Stuart has extensive experience in methods for estimating causal effects and dealing with the complications of missing data in experimental and non-experimental studies, particularly as applied to mental health, public policy, and education. She has published influential papers on propensity score methods and generalizing treatment effect estimate to target populations and taught courses and short courses on causal inference and propensity scores to a wide range of audiences.  Her primary areas of application include mental health, substance use, and policy evaluation, including co-directing the JHSPH Center for Mental Health and Addiction Policy Research. She frequently serves as a statistical consultant for evaluations of policies and programs across a range of applied areas, including gun violence prevention, education, and opioids. Stuart is a Fellow of the American Statistical Association and has been recognized with the mid-career award from the Health Policy Statistics Section of the American Statistical Association, the Gertrude Cox Award for applied statistics, and the Myrto Lefkopoulou award from the Harvard University Department of Biostatistics.

Rebecca Williams

Rebecca G. Williams, MSPH

Director of Academic Innovation and Outreach

Rebecca G. Williams first began working with the Center for Gun Policy and Research in 2017 as a Graduate Research Assistant. In 2018, Rebecca began working full-time with the Center as a Research Data Analyst then the Center’s Research Program Manager and was promoted to Research Associate in 2020. At the Center, Rebecca is most intimately involved with projects related to community-oriented policing, proactive gun law enforcement, and the development of educational opportunities and programs on gun violence prevention research and policy. Rebecca has a strong background in community-based participatory research through which she has worked alongside communities of color as well as with children and families with special health care needs to create systemic change for equitable health outcomes. Her research interests include correctional health care reform, nature-based violence interventions, interactive pedagogical models to advance gun violence prevention advocacy, and how counterproductive gender norms influence male development. Rebecca earned her BS in Health and Wellness Promotion and BA in Interdisciplinary Studies summa cum laude from the University of North Carolina at Asheville in 2014 and her MSPH in Health Policy and Management from the Johns Hopkins Bloomberg School of Public Health in 2019.  

Marisa Booty

Marisa Doll Booty, MHS

Research Data Analyst

Marisa Doll Booty earned her MHS in Mental Health from the Johns Hopkins Bloomberg School of Public Health. While working for her MHS, Marisa completed a thesis with the Moore Center for the Prevention of Child Sexual Abuse on recidivism outcomes for juveniles who have sexually offended. She began working with the Center for Gun Policy and Research as a student and transitioned to full-time staff upon graduation. Marisa is interested in criminology, specifically penology, and how juveniles and other vulnerable populations interact with components of the criminal justice system.

Chelsea Montero

Chelsea Montero

Senior Administrative Coordinator

Chelsea Montero has more than twenty years of senior-level executive management support experience. Her philosophy centers on what role she can play in helping others. With an educational background in art and a creative design enthusiast, Chelsea incorporates this into her take on presentation, problem-solving, and overall function in the office. She practices a streamlined and intuitive approach to assistance. It rests on empathy, efficiency, astute problem solving, and a sense of humor.

Shani Buggs

Shani Buggs, PhD, MPH

Affiliated Research Analyst

Shani Buggs is a Postdoctoral Fellow with the Violence Prevention Research Program at the University of California Davis. Her primary areas of research include community-level gun violence prevention programs and policies, comprehensive approaches to reducing violence through policies and programs at the local, state, and federal levels, and intersections between drugs, drug law enforcement, and gun violence. Buggs has worked for years with Baltimore Mayor’s Office, Police Department, and other city agencies and leaders to help coordinate efforts and provide technical assistance to enhance Baltimore’s violence reduction and prevention strategies. She completed her graduate degree in Public Health and her doctorate in Health and Public Policy at the Johns Hopkins Bloomberg School of Public Health.

Jeffrey Swanson HeadshotJeffrey Swanson

Visiting Scholar

Jeffrey Swanson is professor in Psychiatry and Behavioral Sciences at Duke University School of Medicine and a Visiting Scholar at the Johns Hopkins Center for Gun Policy and Research. Swanson is a sociologist who collaborates across disciplines to build evidence for policies and laws to reduce firearm-related violence and suicide, and to improve outcomes for adults with serious mental illnesses in the community. He is an author of over 200 publications on subjects including the social environmental context of violence in mental illness, implementation of state firearm restrictions related to mental health adjudications, effectiveness of involuntary outpatient commitment, and psychiatric advance directives. Swanson lead the research group that published the first empirical evaluations of risk-based, temporary firearm removal laws in Indiana and Connecticut, precursors to Extreme Risk Protection Order laws that were later adopted in many states. He received the 2011 Carl Taube Award from the American Public Health Association and the 2010 Eugene C. Hargrove, MD, Award from the North Carolina Psychiatric Foundation, both for outstanding career contributions to mental health research. Swanson served as a member of the John D. and Catherine T. MacArthur Foundation Research Network on Mandated Community Treatment and the Methods Core of the Robert Wood Johnson Foundation Public Health Research Program. He frequently serves as a consultant to policymakers at the national and state levels.

Douglas Foster HeadshotDouglas Foster

Research Assistant

Douglas Foster is a research assistant with the Johns Hopkins Center for Gun Policy and Research. His work primarily focuses on community relations and understanding the perceptions and beliefs that Baltimore residents have of peacekeepers in the community, including the police. Foster's previous experiences interacting with the community have enabled him to observe and understand the dynamic between peacekeepers and citizens. His community-building work began in 2005 when he worked with an organization called Clean Water Action. He has been a philanthropist, and catalyst for societal improvement for the better part of eight years. Foster is a Baltimore-native and is dedicated to improving positivity in the city.