Welcome to Requisite Consulting, Singapore, led by Professor David Bruce Matchar. Prof. Matchar is a Professor of Medicine at Duke University in the United States, Director of the Duke Center for Clinical Health Policy Research, and the Inaugural Director of the Programme in Health Services and Systems Research (HSSR) at Duke-NUS Medical School, Singapore.

Meet the Lead Team


  • With over 35 years of experience, Professor Matchar has dedicated his career to promoting evidence-based decision-making in healthcare. His work spans a wide range of clinical and public health policy issues, involving researchers from multiple disciplines under a common systems-oriented framework. His recent projects extend across Southeast Asia, the Pacific Islands, the US, and Europe.

    Prof. Matchar's research addresses complex healthcare challenges through:

    • Applying simulation modeling to forecast health system needs, such as projecting the impact of population aging on stroke prevalence and healthcare resource requirements in Singapore.

    • Developing practical tools to assess and segment populations based on health and health-related social needs, including the creation of the Simple Segmentation Tool (SST)©. The SST identifies patient-level health service needs across various healthcare settings and communities, enabling more targeted and efficient care delivery.

    • Utilizing systems thinking approaches, particularly System Dynamics modeling, to analyze complex health systems issues and design effective interventions. This involves collaborative group facilitation, using methods such as Group Model Building to develop shared conceptual frameworks among stakeholders. This approach has been applied to challenges in chronic disease management, health workforce planning, and healthcare financing reforms.

    In 2022, as a Visiting Senior Research Fellow at Green Templeton College, Oxford, he focused on providing guidance for regional health systems developing innovative services under Singapore's emerging national capitation-based payment scheme. He also collaborates with a WHO advisory group to advance systems thinking in global health systems strengthening.

    Dr. Matchar served on a committee for the National Academy of Medicine (formerly the Institute of Medicine) that produced the report "Treatment of Post-Traumatic Stress Disorder: An Assessment of the Evidence" for the VA and has presented to a congressional subcommittee. He has authored policy reports for the Medicare Coverage and Assessment Committee, the Agency for Healthcare Research and Quality, the American College of Physicians, the American Academy of Neurology, and the American Heart Association.

    Before relocating to Singapore in 2008, Professor Matchar led the Requisite Consulting Group, which provided consultancy services to industry leaders in health services and health economic analyses. Requisite Consulting, Singapore, continues this legacy, integrating rigorous research with practical solutions. The firm leverages 20 years of experience in Singapore and internationally, utilizing System Dynamics and other systems thinking methods to empower stakeholders in navigating the rapidly changing healthcare landscape.

  • John P. Ansah, PhD, is a Lead Systems Modeling Consultant at Requisite Consulting in Singapore. He brings a wealth of international experience to this role, having previously worked at Duke-NUS in Singapore and as an Assistant Professor within the Center for Community Health Integration at Case Western Reserve University.

    Dr. Ansah has over a decade of experience in applying simulation modeling to complex health policy issues. His work, which utilizes computational modeling and active stakeholder involvement, demonstrates his deep understanding of intricate health systems challenges and his ability to inform policy and interventions to improve health outcomes.

    In his current position at Requisite Consulting, Dr. Ansah leverages his expertise in systems science and health systems improvement to provide consulting services to clients. His research interests broadly cover the evaluation of health system-wide impacts of complex health and social care interventions.

    Dr. Ansah holds a PhD degree in Systems Science methodology of System Dynamics from the University of Bergen, Bergen, Norway.