Search

Geoff Scahill has over 20 years of experience working in and managing international development programs. He has worked extensively within Papua New Guinea (PNG) and the Pacific – predominantly in Indonesia, Fiji, Samoa, and the Solomon Islands. He brings a long history as a health sector professional and has held roles as a health management advisor and health systems adviser in Pacific Island Countries. Geoff draws on his background in finance and economics to work with counterparts to increase efficiencies within the programs Abt Global delivers.

Jennifer S. Riggs, Ph.D., brings her extensive research, policy, and nursing experience to improve care for patients, especially older adults. Her clinical area of expertise is Medicare-certified home health and home and community-based care for adults and older adults with multiple co-occurring chronic conditions and complex care coordination needs.

Marianne El-Khoury is a seasoned health professional with a proven track record of leading and managing large-scale health programs. At Abt, she has held senior management and technical roles on USG-funded projects in health systems strengthening, infectious diseases, and private sector health. She has also led research and evaluation studies in family planning and reproductive health, maternal and child health, and health financing.

Joe Donahue is an environmental policy specialist and portfolio manager with more than 15 years of experience supporting governments in developing and implementing policies and programs focused on climate change, clean energy, ozone layer protection, and solid waste management. His work spans both domestic and international programs and initiatives. Technical areas of expertise include climate change mitigation strategies; international capacity building; greenhouse gas quantification methods; short-lived climate pollutants, especially methane, black carbon, and hydrofluorocarbons; and clean energy policies.

Allan Porowski joined the Social and Economic Policy Division of Abt Global in 2014 as a principal associate. He is a leading expert in the design, execution and analysis of randomized controlled trials, quasi-experimental studies and national cross-site evaluations of education, health and other social interventions.

Eduardo Castellon has two decades of experience helping public sector clients—from the U.S. Agency for International Development (USAID) and the U.S. Postal Service (USPS) to the Department of Housing and Urban Development—grow and refine their operations and impact. He has extensive experience delivering consulting expertise focused on artificial intelligence (AI), supply chain, procurement, financial management, and advanced analytics. His technological, consultative, and entrepreneurial skills help clients find new ways to address challenges ranging from affordable housing to homelessness to guaranteed income. He also has extensive expertise in technical assistance and implementation (TA&I) approaches. And his management experience includes developing high-performing teams through skills and career development and succession planning.

Brooke Abrams is a trained political scientist and researcher. With over 11 years of experience, she specializes in applied housing and health, bringing expertise in managing and contributing to place-based, mixed-method, and community-centered solutions. Her work spans research, evaluation, and technical assistance (TA) projects across diverse policy domains, delivering innovative and tailored strategies to drive impactful change.As a Client Solutions Architect at Abt, Abrams plays a pivotal role in designing client-focused frameworks and solutions that emphasize rigorous, data-informed, multi-disciplinary, and population-tailored design. She specializes in community-specific, monitoring, evaluation, and technical assistance approaches to engage and work alongside persons with lived expertise.

In his career as a senior finance and operations executive, Rehberger most recently served as the Senior Vice President, Chief Financial Officer of Engility, a Virginia-based government contractor.  He held similar positions with TASC from 2010 until its merger with Engility in 2015.  Rehberger helped guide both companies as the government industry cycled through a severe downturn and recovery, counseling the Board of Directors regarding strategy, enterprise risk management, cyber security, and compensation.  He previously held executive positions with telecommunications firms XO Communications and MCI. In 2017, Virginia Business awarded Rehberger the Virginia CFO of the Year award for his outstanding commitment to financial stewardship and dedication to the success of Engility.

Clark Abt, an engineer, environmentalist, entrepreneur, educator and social scientist, is the founder and past president of Abt Global Inc. He served as Abt’s President from 1965 to 1985, Chairman of the Board of Directors from 1986 to 2005, and was then elected Chairman Emeritus. He is the author of 10 books on social and economic policies and advanced technologies, as well as many articles.Clark Abt was born in Cologne, Germany, in 1929, and came to the United States in 1937. He entered the Massachusetts Institute of Technology as a freshman in aeronautical engineering in 1947 and graduated with a bachelor's degree in general engineering in 1951. He then served four months in the Merchant Marine as an ordinary seaman, followed by a year at Johns Hopkins University as an English instructor, obtaining an M.A. from the Department of Writing, Speech and Drama for this master thesis, “A Year of Poems.”

Daniel Gubits conducts research in the areas of housing, homelessness, economic self-sufficiency and disability policy. Gubits’ expertise is in econometric modeling, data analysis, and random assignment program evaluation.Gubits serves as the director of analysis for the Family Options Study, conducted for the U.S. Department of Housing and Urban Development (HUD). He is also leading the impact analysis work for the Social Security Administration’s Benefit Offset National Demonstration (BOND) project. Both of these are random assignment impact evaluations.