The Research Onion Explained

As many aspiring researchers learn during a postgraduate degree, Saunders, Lewis, and Thornhill’s (2011) metaphor of the “Research Onion” can be extremely helpful when designing a study. Thinking about research as a multi-stage journey — one that involves not only data collection and analysis but also philosophical and methodological choices — keeps the whole process coherent and appropriate (Sahay, 2016).

Students spend years on PhDs and other extended projects, so a poorly designed research process can be costly for a career. If a student assumes that research simply means working out which data to gather and which analysis to run, the quality of the study is likely to suffer (Saunders and Tosey, 2013). Few people will then take its findings seriously — which rather defeats the purpose of research (Leung, 2015).

For that reason, this article defines and explains the main features of the Research Onion in simple terms, and briefly discusses why you might use it to guide the planning of your project. A full list of references (in Harvard style) is given at the end.

What Is the Research Onion?

The Research Onion is a metaphor devised by Saunders et al. (2011). It illustrates how the “core” of a study — data collection and analysis — can only be coherent when it rests on an understanding of the other essential elements of a research design: the research philosophy, approach, strategy, methodological choice, and time horizon.

The metaphor is useful because effective research involves peeling away several layers. Although you can peel the onion from the inside out (Sahay, 2016), the simplest approach is to start with the outer layer and work inwards (Saunders et al., 2011).

Why Would I Use the Research Onion?

If you want others to take your work seriously, you need to show that your techniques and procedures are reasonable, credible, coherent, and — above all — not arbitrary. As we noted in our article on systematic literature reviews, good researchers, particularly in fields such as healthcare, will appraise the methodological quality of a study.

Decide how to gather and analyse data arbitrarily, and your work is likely to be of little value to others. Think carefully about the essential design elements, consider how they relate, and explain and justify them, and others will have good reason to treat your findings as reliable (Saunders and Tosey, 2013).

It is worth noting that, while the Research Onion is widely used and effective, alternatives exist. We won’t cover them here, but Melnikovas (2018) is a good starting point. For its simplicity and clarity, though, the Research Onion remains a strong default choice.

Peeling Back the Layers of the Research Onion

Research Philosophy

A research philosophy establishes the epistemological, axiological, and ontological foundations of a study (Denscombe, 2008; Saunders and Tosey, 2013). In plain English, it is the researcher’s view of what counts as acceptable knowledge. Fittingly, then, it is the outermost layer of the onion.

Several research philosophies exist, including interpretivism, positivism, realism, and pragmatism (Creswell, 2014). When designing your study, get to know the main features of each, because the decision you make here will shape every later one.

Research Approach

Your research approach determines the broad mode of reasoning you adopt (Burney, 2008). Certain approaches pair naturally with certain philosophies — for example, the “top-down” (deductive) approach is often paired with positivism (Wilson, 2010).

Alongside the deductive approach, the inductive approach is the other main option (Zalaghi and Khazaei, 2015). A full treatment is beyond the scope of this article, but Trochim (2006), Wilson (2010), Saunders et al. (2011), and Zalaghi and Khazaei (2015) are all valuable resources.

Research Strategy

A research strategy is the overarching plan you use to answer your research question (Saunders and Tosey, 2013). Strategies range from ethnography to experiment, and the easiest way to grasp the concept is through an example.

Consider the case-study strategy, in which a phenomenon, individual, or entity is investigated within its real-life context (Yin, 2003). You might apply it by examining an event such as the Watergate scandal, or by investigating paediatric pain-management practices among nurses (Heale and Twycross, 2018).

Methodological Choice

Methodological choice — choosing between quantitative, qualitative, multi-method, mono-method, and other designs — is basic but critical (Saunders and Tosey, 2013). Before deciding, weigh your available time, resources, and skills.

Time Horizon

The fundamental choice at the time-horizon layer is whether to take a “snapshot” of a population at a single point in time (a cross-sectional horizon) or to gather data at multiple points (a longitudinal horizon) (Bryman, 2012).

Techniques and Procedures

As the innermost layer, your decisions about how to gather and analyse data should follow from every layer you have already peeled back (Flick, 2011).

Things to consider include how you will collect your data (for example, questionnaires or interviews), how you will sample your target population (probability or non-probability sampling), how you will determine sample size (for example, power calculations), who your participants will be, and what method of analysis you will use (for example, thematic analysis or a statistical technique).

References

Burney, S. M. A. (2008) Inductive and Deductive Research Approach. University of Karachi.

Bryman, A. (2012) Social Research Methods. 4th edn. Oxford: Oxford University Press.

Creswell, J. W. (2014) Research Design: Qualitative, Quantitative, and Mixed Methods Approaches. 4th edn. Thousand Oaks, California: SAGE Publications.

Denscombe, M. (2008) Communities of practice: A research paradigm for the mixed methods approach. Journal of Mixed Methods Research. 2 (3), 270–283.

Flick, U. (2011) Introducing Research Methodology: A Beginner’s Guide to Doing a Research Project. London: SAGE Publications.

Heale, R. and Twycross, A. (2018) What is a case study? Evidence-Based Nursing. 21, 7–8.

Leung, L. (2015) Validity, reliability, and generalizability in qualitative research. Journal of Family Medicine and Primary Care. 4 (3), 324–327.

Melnikovas, A. (2018) Towards an explicit research methodology: Adapting the research onion model for futures studies. Journal of Futures Studies. 23 (2), 29–44.

Sahay, A. (2016) Peeling Saunders’s Research Onion.

Saunders, M. and Tosey, P. (2013) The layers of research design. Rapport, Winter, 58–59.

Saunders, M., Lewis, P., and Thornhill, A. (2011) Research Methods for Business Students. 5th edn. Harlow: Pearson.

Trochim, W. M. K. (2006) The Research Methods Knowledge Base. 2nd edn.

Wilson, J. (2010) Essentials of Business Research: A Guide to Doing Your Research Project. London: SAGE Publications.

Yin, R. K. (2003) Case Study Research: Design and Methods. 3rd edn. Thousand Oaks, California: SAGE Publications.

Zalaghi, H. and Khazaei, M. (2015) The role of deductive and inductive reasoning in accounting research and standard setting. Asian Journal of Finance and Accounting. 8 (1), 23–37.