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Michelle Roozeboom-Baker is an applied statistician and health data analytics leader with decades of experience analyzing national Medicare and Medicaid administrative data and partnering with the Centers for Medicare & Medicaid Services (CMS).

Lauren Pittenger comes to Abt with more than 20 years of experience working in or as a consultant to federal government agencies. She has strong grounding in research and research-based consulting to government clients. She also has extensive experience leading and growing business, managing technical and scientific projects, and coaching and supporting account teams. She has served as a director at Guidehouse, scientific program manager at Booz Allen Hamilton, and lab manager at the U.S. Department of Agriculture. She has worked with the Centers for Disease Control and Prevention (CDC), Food and Drug Administration (FDA), the Canadian Public Health Laboratory Network, the Gates Foundation and the Association of Public Health Laboratories.

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.

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.

Michael R. Anderson is Chief Executive Officer of MedAccess, a not-for-profit social-finance company based in London. He has expertise in global development, health, nutrition, and climate issues. Anderson has worked in the public, private, and nonprofit sectors in Africa, the Middle East, and India. He held multiple roles within the U.K.’s Department for International Development (DFID) from 2003 to 2013, the final one being Director General . He subsequently became the first salaried CEO of the Children’s Investment Fund Foundation, one of the largest philanthropies in Europe. 

Jessen Carroll is a human resources (HR) professional with more than 20 years of experience overseeing all aspects of HR, organizational communications, governance, and administration functions. She has experience leading organizational integrations and change management efforts. She also has operations management, business analysis, business process improvement, and project management experience. She can balance tactical day-to-day operational needs with a strategic grasp of long-term business objectives. 

ZeAmma Brathwaite has over 20 years of experience partnering with private organizations and federal agencies to improve access to care and health outcomes for individuals and communities. A certified project management professional, Brathwaite has extensive experience leading multidisciplinary teams in the design, implementation, and evaluation of complex, large-scale transformation efforts using improvement science methods and tools to accelerate change.

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.

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

Jake Zebell is a technology leader with more than 20 years of experience in federal modernization, enterprise architecture, applied AI, and secure system delivery.