Viva Questions for Public Health

Public Health vivas sit at the intersection of epidemiology, policy, and social science. Examiners will expect you to demonstrate methodological rigour alongside an understanding of how your research translates into real-world health interventions or policy recommendations. Whether your work is quantitative, qualitative, or mixed methods, you'll need to show awareness of population-level thinking, health inequalities, and the practical constraints of implementing evidence in complex systems.

Public health research is inherently applied. Unlike some academic disciplines where theoretical contribution is enough, public health examiners will almost always ask: so what should we do about it? Your findings need to travel beyond the thesis and into the worlds of policy, commissioning, and practice. Being able to articulate that journey – with appropriate caveats about the strength of your evidence – is central to a successful viva.

Questions about your research

Public health examiners are trained in epidemiology and will scrutinise your study design with a sharp eye for bias, confounding, and the validity of your exposure and outcome measures. They'll also be interested in the practical challenges of your research – how you accessed data, engaged with communities, or navigated the ethics of population-level research. If your work uses routine data or linked datasets, expect questions about data quality, completeness, and the assumptions you made in cleaning and analysing it.

• What public health problem does your research address, and why is it a current priority?
• How did you define your study population, and what were the implications of your inclusion and exclusion criteria?
• What epidemiological study design did you use, and why was it the best available option for your research question?
• How did you collect your data, and what were the main challenges – access, completeness, or quality?
• How did you handle confounding in your analysis – through design, statistical adjustment, or both?
• What measures did you use to assess exposure and outcome, and how valid and reliable are they?
• How did you address the main sources of bias – selection bias, information bias, recall bias?
• What ethical considerations were particularly important in your research, and how did you navigate them?
• How did you engage with communities, patients, or stakeholders during the design or conduct of your research?
• Were there any data linkage, coding, or classification issues, and how did you manage them?
• How did you handle multiple testing, subgroup analyses, or the risk of data dredging?

Questions about theory and literature

Public health draws on a wide range of conceptual frameworks – from the social determinants of health model to behaviour change theories, health economics, and systems thinking. Examiners will want to see that you've chosen your framework for a reason and that it genuinely informs your analysis rather than being cited in the introduction and then forgotten. They'll also be interested in how your work connects to the wider policy and epidemiological evidence base.

• What conceptual or theoretical framework underpins your research – a socio-ecological model, a behaviour change framework, or something else?
• How does your work contribute to the epidemiological evidence base in this area?
• What are the key systematic reviews, meta-analyses, or landmark studies relevant to your work, and how does your study compare?
• How does your research relate to current public health policy, strategy, or targets?
• Are there international comparisons or cross-country studies that put your findings in context?
• How has the public health landscape – policy, funding, or population health trends – evolved during your PhD?
• How does your work engage with the social determinants of health or structural drivers of the problem you studied?

Questions about contribution and impact

Public health examiners will press you on what your findings mean in practice. They'll want to know who should act on your results, what they should do, and how confident you are in that recommendation. Be prepared to distinguish between what your evidence supports and what you believe – examiners will respect intellectual honesty about the limits of your findings.

• What does your thesis contribute to public health knowledge or practice that is genuinely new?
• What are the specific policy implications of your findings – who should act, and what should they do?
• How could your research be used to design, implement, or evaluate a public health intervention?
• What would you recommend to a Director of Public Health or commissioner based on your findings?
• How do your findings speak to health inequalities – do they affect some populations more than others?
• What is the cost-effectiveness case for acting on your findings, even if you haven't formally modelled it?

Tough follow-ups your examiners might ask

Public health examiners know that population-level evidence is inherently messy. They'll push on the gap between association and causation, the generalisability of your findings to different populations, and whether your recommendations are proportionate to the strength of your evidence. They'll also test your ability to communicate complex findings to non-academic audiences – because that's what public health practitioners have to do every day.

• Your study is observational – how confident are you in drawing a causal conclusion from these data?
• How would your findings differ in a population with different demographics, health behaviours, or health system structures?
• A policymaker challenges you: why should limited resources be directed at this problem when there are competing priorities? How do you make the case?
• What are the potential unintended consequences of implementing your recommendations at scale?
• How would you design a follow-up study – whether a trial, a natural experiment, or a linked data study – to strengthen the evidence for action?
• If your key finding turned out to be driven by residual confounding, what would that mean for your recommendations?
• How would you explain your main finding to a member of the public or a journalist in one sentence?

Ready to practise? These are the kinds of questions your examiners will ask – but in a real viva, they won't stop at the first answer. They'll follow up, probe deeper, and test how well you can think on your feet. Try VivaCoach to practise with AI-powered follow-up questions tailored to your thesis.

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