Quick answer: Philosophical misalignment, not weak data, sinks most doctoral vivas. The Research Onion links research philosophy to method, and applying it properly in risk, security, safety and resilience research prevents that failure before it happens.
Originally published on LinkedIn: 29 March 2026.
Philosophical misalignment is cited as a primary weakness in roughly three-quarters of doctoral viva rejections, a mismatch between what a researcher claims to believe about reality and the tools they use to study it. The Research Onion, developed by Saunders, Lewis and Thornhill, exists to prevent exactly that failure.
Six Layers, One Argument
The model works through six concentric layers: Philosophy, Approach, Strategy, Choices, Time Horizons, and Techniques and Procedures. Each outer layer grounds the one inside it. The point is not to produce a diagram for a methodology chapter, it is to force a researcher to peel back assumptions until the data collection method sits on solid philosophical footing.
Philosophy Is the Foundation
At the outer layer sits research philosophy: beliefs about the nature of reality and how knowledge is validly acquired. Positivism treats reality as objective and measurable, the basis for hypothesis testing. Interpretivism holds that reality is socially constructed and multiple, requiring the researcher to interpret participants' meanings. Critical realism sits between the two. Pragmatism sidesteps the argument and lets the research question dictate the method, which is why it so often produces mixed-methods designs. Get this layer wrong and everything built on top of it is unstable.
From Theory to Data and Back
The next layer, approach, governs the direction of reasoning. Deductive work starts with theory and tests a hypothesis. Inductive work starts with observations and builds theory from them. Abductive reasoning moves back and forth between theory and data. One persistent error is assuming quantitative research is always deductive and qualitative always inductive, it is not, and treating the pairing as automatic is a shortcut examiners notice.
Strategy follows: experiments, surveys, case studies, ethnography, action research and grounded theory each answer a different kind of question, and the choice has to be justified against the alternatives that were rejected, not just described in isolation.
Application in Risk, Safety and Security Sciences
Outside business schools, the Onion has proven adaptable. In risk, safety and security research it structures how cybersecurity and fraud studies classify risk by origin, and how integrated risk assessment work combines probabilistic tools such as Bayesian networks with broader systemic analysis. A recurring finding in this space is that uncertainty in the choice of model itself can outweigh uncertainty in the parameters fed into it, a strong argument for treating model selection as a philosophical decision rather than a purely technical one.
Rigour Is a Discipline, Not a Checklist
Lincoln and Guba's trustworthiness framework, credibility, transferability, dependability and confirmability, remains the benchmark for qualitative rigour, alongside sustained attention to reflexivity, the researcher's awareness of how their own identity and assumptions shape what they find. None of this substitutes for the harder discipline the Onion demands, justifying every methodological decision back to first principles.
Is your current research design a collection of random tools, or is it a defensible philosophical argument?
That question applies as much to a risk assessment methodology built for a client as it does to a doctoral thesis. A model chosen without reference to the underlying assumptions about how the risk environment actually behaves will not survive serious scrutiny from a board, a regulator or an examiner.
If your organisation is building a risk, safety or security research programme, a methodology review, or preparing analytical work for scrutiny by a board, regulator or academic panel, Tony Ridley works with clients to pressure-test the philosophical and methodological coherence behind it before it is exposed to that scrutiny. Contact us to discuss your requirements.