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Dr. Michael Plotzke is a senior health economist with expertise in the area of Medicare payment policy, the organization of healthcare providers and quality measurement. His work typically involves the analysis of large datasets such as Medicare claims, assessment and enrollment data. Dr. Plotzke serves as principal investigator for multiple projects with the Centers for Medicare & Medicaid Services.  On the “Home Health Prospective Payment System and Hospice: Analysis Support and Monitoring” project, Dr. Plotzke leads a team of researchers in analyzing trends in Medicare hospice and home health usage and constructing large-scale payment reform options for both benefits.  Dr. Plotzke also leads the “Evaluation of the Medicare Care Choices Model” project that evaluates a new payment model for end-of-life care that is being tested with 141 hospice providers.  This project involves analysis of existing administrative data and collection of new data through surveys of caregivers, surveys of hospice providers and in-depth case studies of hospice providers participating in the model.

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.”

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.

Baris Yener has more than 25 years of experience in executive leadership, growth strategy development, and organizational transformation. His business-development and project work has involved a wide range of clients, including the World Bank, Department of Defense, Department of Homeland Security, Centers for Disease Control and Prevention, and other private sector and federal agencies.As Chief Client Officer at Abt, Yener leads client strategy and growth to ensure the voice of the customer drives investment decisions, capability development, and market execution. 

Mariandrea Chamorro has 20 years of experience managing international development programs. She has provided oversight for the high-quality and compliant execution of large flagship USAID programs while contributing to business development. Chamorro’s areas of expertise include prevention of vector-borne diseases, infectious diseases, maternal and child health, and health systems strengthening. Her clients have included the U.S. Agency for International Development (USAID), the Australian Department of Foreign Affairs and Trade (DFAT), and the UK’s Foreign Commonwealth & Development Office (FCDO). 

Lisa Simeon is Abt Global’s Chief Operations Officer.  In this role, Simeon is establishing a global operations function to cover all aspects of project management. It will include continuous improvement and scalability of Abt’s standards, processes, and digital platforms for project start-up and closeout, workforce planning, risk management, and quality review to achieve strong financial performance and ensure client satisfaction across the company. She will continue to oversee Human Resources and will add responsibility for global security operations and emergency response to her portfolio.

Chris Long has over 35  years of management consulting and service delivery expertise in the public-sector market. At Abt, he is focused on shaping and driving delivery of strategy and transformation solutions to our clients. He provides executive oversight of operations, growth, delivery, and innovation, while fostering collaboration enterprise-wide.

William Tuleu leads strategic growth initiatives across the company's U.S. foreign assistance and domestic portfolios.

Matt Bugbee is a federal technology executive with almost three decades of experience leading digital modernization, enterprise IT, and business growth initiatives for civilian agencies.