The People behind TheoQuest.
TheoQuest is led by a team of evaluation experts from the world's leading institutions. Based in the UK and the US with an international collaborative network, we apply our expertise to help you achieve your goals.
Sabine Yeung
Co-Founder & Principal Consultant
Cambridge (PhD, In Progress) | Oxford (MSc) | HKU (BA)
Sabine's starting point is always the same: what are people actually experiencing, and what does the data say about it? With over a decade of research experience across academia, healthcare and the non-profit sector, she has spent her career helping organisations move past assumptions and build strategies grounded in how people genuinely think, feel and behave.
With a background in cognitive, social and health psychology, her doctoral research at the University of Cambridge looks at how pregnancy, motherhood and lifestyle intersect with physical health and psychological wellbeing — work that involves designing complex studies and managing large-scale datasets from the ground up. That same rigour shapes every client project she leads: from the initial research design through to the final insight report, nothing is left to guesswork.
Sabine specialises in survey and experimental design, longitudinal impact studies and quantitative data analysis. At TheoQuest, she brings that expertise to clients who need to understand their people better, whether that means evaluating a new initiative, auditing internal data or building a measurement framework that will hold up over time.
Georgios Argyros
Co-Founder & Principal Consultant
Edinburgh (PhD, In Progress) | Oxford (MSc) | UoL (BSc) | RAUL (BA)
Georgios works at the intersection of data, biology and human behaviour, specifically looking at how the choices we make about food, sleep and lifestyle shape our mental health over time. His research is driven by a belief that the best decisions, whether in public policy or in business, come from understanding real patterns in real populations rather than relying on assumptions.
His doctoral research at the University of Edinburgh investigates how nutrition affects depression and anxiety in early adolescence, drawing on national multi-cohort datasets and advanced statistical modelling. He has extensive experience handling large and complex datasets, navigating the gaps and inconsistencies typical of real-world data, and turning them into clear, actionable findings.
Georgios is passionate about equity, ensuring research reflects the full diversity of human experience. At TheoQuest, he channels his background into evaluating the long-term impact of health and wellness initiatives. Based in the United States, Georgios serves as TheoQuest's primary point of contact for North American clients and international partnerships.
Sara Rashid
Learning & Engagement Partner
Cambridge (PhD, In Completion) | York (MSc & BSc) | CMI Level 5 Leadership & Management
Sara thinks a lot about how people learn — not just what information they receive, but how they process it, retain it and actually use it. With a background in cognitive psychology, child development, memory and community accessibility, she brings a rare combination of scientific depth and practical training experience to her work with organisations.
Her doctoral research at the University of Cambridge explores how episodic memory first emerges in early childhood, which sheds light on the fundamental mechanics of how humans build understanding from experience. Alongside her academic work, she holds a CMI Level 5 qualification in Leadership and Management, meaning she is equally at home translating research findings for a boardroom as she is designing hands-on workshops for frontline teams.
Sara is a fluent speaker of British Sign Language (BSL) and a committed advocate for inclusive learning environments. At TheoQuest, she designs and delivers the training programmes and capability-building workshops that help client teams develop lasting confidence in data, research and evidence-based decision-making.
Zoe Hemsley
Clinical Advisor
Cambridge (BA, MB BChir (Medicine & Surgery))
Zoe's interest lies in the space where clinical care meets evidence: what the research says, and what that means for the person in front of you. A newly qualified doctor undertaking her Foundation Training at Chelsea and Westminster Hospital, she brings a clinician's eye for real-world nuance to questions that are too often answered from a desk.
Her academic path has combined medicine with a sustained research thread. Alongside her clinical training, Zoe has developed research experience across dermatology, cognition and child health, including a research placement at Cambridge investigating the effects of infection on children's cognition, and a research internship at King's College London's St John's Institute of Dermatology. She has received national recognition, having been awarded the British Society for Dermatological Surgery Medical Student Essay Prize for her work on digital consent in modern care models.
At TheoQuest, Zoe provides clinical insight and advisory input on projects that touch health, wellbeing and patient experience, ensuring that client strategies, health metrics and intervention models remain medically sound, ethically grounded and focused on genuine human impact.