As an environmental gerontologist, Sojung Park studies how housing and neighborhood environments shape aging in place among older adults, with particular attention to those who are most vulnerable: those who are low-income, cognitively impaired, and living alone. Building on a person–environment fit framework, she conceptualizes aging in place not as a function of individual health or service supply alone, but as the outcome of a dynamic fit across the economic, service, social, and spatial dimensions of where older adults live.
A central thread of Park’s work concerns housing as a platform for healthy aging. Her longitudinal and review studies examine how subsidized and supportive senior housing relates to older residents’ health, cognitive function, support access, and well-being across the life course, showing, for example, how social engagement and neighborhood cohesion help explain the link between subsidized housing and cognitive function, and how community-based housing type shapes end-of-life resources and where older adults ultimately die.
A second thread turns to the neighborhood and community environment. Park investigates how the social, physical, and service characteristics of neighborhoods, including geographic access to local resources, enable or constrain support, participation, and aging in place. Her cross-national and cross-cultural studies compare age-friendly environments and community-based care arrangements across the United States and Korea, examining why supports and services that are available to some older adults remain inaccessible or unused for others.
Across this work, Park increasingly considers how housing and community settings can coordinate and connect older adults to support, pointing toward community-based models of care that strengthen equitable aging in place.
Current Work
Park’s current work extends this research program in two directions. The first is a book project on alternative housing communities in Korea, grounded in direct site visits and interviews. Following people across the life course (young adults in housing cooperatives, older adults in cohousing and care-oriented housing, identity-based communities, and village- and neighborhood-anchored housing), the project asks when living together becomes solidarity and when it becomes a survival strategy, how care is distributed, and whether such communities supplement public systems or quietly absorb what those systems leave undone. Anchored in frameworks of the social reproduction of housing, the solidarity of precarity, and housing as commons, it brings a qualitative, place-based lens to the same questions Park studies quantitatively in the United States, and lays the groundwork for forthcoming English-language scholarship.
The second extends Park’s person–environment fit framework to aging with and into disability. This emerging line of work examines how middle-aged and older adults with disabilities experience fit and misfit across the multiple domains of their environments, with particular attention to the service divide between aging-services and disability-services systems, where eligibility rules, institutional missions, and categorical classifications can leave people fully served by neither. A scoping review and a complementary qualitative study consider how this divide is experienced differently depending on disability timing, that is, by those aging with a long-standing disability versus those aging into disability in later life.
Byron aims to improve health and social services by advancing implementation science. His scholarship has contributed to the development, specification, tailoring, and evaluation of implementation strategies, as well as methods for studying implementation processes, mechanisms, and outcomes. Through international and interdisciplinary collaborations, he has helped grow implementation science and its application across diverse health and social service systems.
Byron is a Professor and Associate Dean for Research at the Brown School of Social Work at Washington University in St. Louis (WashU), where he co-directs the Center for Mental Health Services Research. He holds secondary appointments in WashU’s Bursky School of Public Health and the School of Medicine, and serves as an Adjunct Professor of Public Health at University College Cork, Ireland.
Supported primarily by the U.S. National Institutes of Health (NIH), he has published more than 200 peer-reviewed articles and other scholarly works. His research has helped shape widely used frameworks, methods, measures, and reporting standards for implementation research. He has been recognized as a Clarivate Highly Cited Researcher and one of Stanford University–Elsevier’s World’s Top 2% Scientists. His honors include a Fulbright Specialist Award, WashU’s Provost’s Research Excellence Award, and the Early Career Award from the Association for Behavioral and Cognitive Therapies Dissemination and Implementation Special Interest Group.
Byron is committed to building capacity in implementation science through teaching, mentorship, and international collaboration. He teaches the doctoral-level course Developing and Evaluating Implementation Strategies in Health and Social Services and has mentored doctoral students, postdoctoral fellows, and faculty members from around the world. He co-directs the Brown School’s National Institute of Mental Health (NIMH)-funded Training Program in Mental Health Services Research and serves as Director of the NIMH-funded Implementation Research Institute. He also serves as faculty for several national and international implementation science training programs, helping prepare researchers to conduct rigorous implementation research and improve health and social care across diverse settings.
He has contributed to the growth and leadership of the field through sustained professional service. He is a former President of the Society for Implementation Research Collaboration, Co-Editor-in-Chief of Implementation Research and Practice, a member of the editorial board of Implementation Science, and a standing member of the NIH Science of Implementation in Health and Healthcare Study Section. Across his research, mentorship, and professional leadership, Byron is committed to strengthening implementation science and supporting the use of evidence to improve health and social care.
Dr. Jason Purnell joined the James S. McDonnell Foundation as President and CEO in 2023, following his leadership in community health improvement at BJC HealthCare. There, he developed health equity programs and introduced an anchor institution agenda focused on investments in high-poverty communities of color.
This work built on nearly a decade of scholarship at Washington University’s Brown School, where Purnell served as Assistant Professor (2011–2017) and Associate Professor (2017–present) of Social Work, founding director of Health Equity Works (formerly For the Sake of All), and faculty director of Thriving Communities at the Center for Social Development. He also held faculty affiliations with the Institute for Public Health, the Prevention Research Center, and the Center for Public Health Systems Science. In 2014, he and his collaborators released the seminal “For the Sake of All” report, addressing African American health in St. Louis and inspiring significant policy changes and programmatic innovations. A follow-up report, “Segregation in St. Louis: Dismantling the Divide,” led to the establishment of an affordable housing trust fund for St. Louis County.
Purnell’s scholarship spans more than 60 peer-reviewed publications, book chapters, and policy reports on the social determinants of health, health equity, and psychological well-being. His work has appeared in journals including JAMA, the Annual Review of Public Health, and the Journal of Clinical Oncology, and his commentary has been featured in CNN.com, the St. Louis Post-Dispatch, and the Boston Review. He was appointed to the 2020 Roundtable on Population Health Improvement of the National Academies of Sciences, Engineering, and Medicine, where he served until 2025 and was a member of the advisory board for the Robert Wood Johnson Foundation’s Health Policy Fellows program.
Purnell holds a bachelor’s degree in Government and Philosophy from Harvard University, a doctorate in Counseling Psychology from The Ohio State University, and a master’s in public health from the University of Rochester School of Medicine and Dentistry, where he also completed a postdoctoral fellowship in a National Cancer Institute’s Cancer Prevention and Control Training Program.
He has been recognized nationally and locally for his contributions to public health and leadership, including being named an Eisenhower Fellow with travel to Rwanda and Spain (2022), one of Modern Healthcare’s Top 25 Diverse Healthcare Leaders (2021), and the St. Louis American’s Person of the Year (2016).
Purnell is on a leave of absence from the Brown School.
Mark R. Rank is widely recognized as a foremost expert on issues of poverty, inequality, and social justice. His research on the lifetime risk of poverty has been groundbreaking, demonstrating for the first time that a majority of Americans will experience poverty at some point during their lives.
To date he has written a dozen books on a range of subjects, including a new understanding of poverty, an exploration of the American Dream, and the role of rugged individualism in shaping patterns of inequality. His most recent book is entitled, The Random Factor: How Chance and Luck Profoundly Shape Our Lives and the World Around Us. In addition, he has published articles in many academic journals across a wide variety of fields.
Dr. Rank is the recipient of numerous awards over the years for his scholarship, books, and teaching, and his research is widely reported throughout the national and international news media. His work is frequently discussed in major news outlets, including various programs on NPR, NBC, CBS, CNN, PBS, BBC, and others. He has written for the New York Times, Washington Post, Guardian, Time Magazine, Globe and Mail, USA Today, Chronicle of Higher Education, and many more.
He has also provided expertise and advice to members of the U.S. Senate and House of Representatives, the White House, and many national organizations involved in issues of economic and social justice. His research was cited by then-President Barack Obama in a major speech on economic mobility, as well as by former presidential candidates Senator Bernie Sanders and Secretary of State Hillary Clinton.
Prof. Rank has developed a website, Confronting Poverty, that allows users to explore in greater depth the issues of poverty and economic inequality. The site, whose centerpiece is an innovative poverty risk calculator, is being used in universities and high schools across the country, along with various social justice and community organizations. To date, the website has had over 2 million page views with visitors from more than 200 countries.
Stephen Roll’s (he/him) research focuses on promoting asset building, debt management, and economic security in lower-income populations. Working within the Center for Social Development, where he is the Director of Research, he is involved in research on cash transfers, child savings, and the role of public and employer-based benefits programs in promoting (or harming) economic and social mobility. Roll serves on the Editorial Review Board of the Journal of Consumer Affairs and as a co-lead of the Grand Challenges for Social Work Network to Reduce Extreme Economic Inequality.
His most recent work focuses on the role of cash transfer programs in improving household balance sheets and economic mobility outcomes, which includes studies of the Expanded Child Tax Credit and six Guaranteed Income experiments in Georgia, North Carolina, and Missouri. He is also leading studies examining the barriers to economic mobility embedded in many public benefits programs.
His work has been featured in numerous media outlets including The Atlantic, The Wall Street Journal, NPR, The Washington Post, and the New York Times, and he has briefed the White House Domestic Policy Council, the Senate Joint Economic Committee, and the United States Supreme Court on the results of his research.
Prior to joining the Brown School, he worked in the private sector as a consultant for Proctor & Gamble.
Joshua Rusow’s (he/him) research primarily focuses on the health and wellbeing of sexual and gender minority youth and young adults—understanding how experiences of stigma and discrimination are associated with relationships, behavior, and mental, physical, and sexual health. His doctoral research highlighted the occurrence of teen dating violence and sexual assault among sexual minority adolescents in different contexts throughout the United States. That work employed longitudinal modeling to identify correlates before and after physical and sexual violence experiences to understand the mechanisms that may contribute to the well-established relationship violence and health disparities observed in sexual minority adolescent populations.
His emerging research focuses on 1) how sexual minority adolescents learn about romantic relationships; 2) how they think about relationships that involve violence; and 3) how experiences of violence (both in and outside of romantic relationships) impact LGBTQ+ youth health. Joshua collaborates with colleagues at Friends Research Institute and San Diego State University on a clinical trial of technology use to build peer relationships in preventing HIV, promote PrEP uptake, and reduce gender-based stigma among gender minority youth and young adults.
Prior to joining the Brown School, Rusow completed a postdoctoral fellowship in the Division of Research on Children, Youth and Families at Children’s Hospital Los Angeles.