This article explains the research onion in simple terms. It builds on the concept of research philosophy, which uses the simple analogy of a tree to demonstrate how philosophy is inherently linked to research design.
What is the research onion?
The research onion was developed by Saunders, Lewis and Thornhill and first appeared in their textbook Research Methods for Business Students in 2007 to describe the stages through which a researcher must pass when developing an effective methodology. In order for your research to have maximum credibility, you must provide explanations and justifications for each level of your methodological decisions. The research onion is basically an extension of the research methods tree. The model has been updated in later editions of the book, which now include a wider range of philosophies (such as critical realism, postmodernism and pragmatism) and a third research approach, abduction.
Video: The research onion made easy
Layers of the research onion
As you can guess, there are different layers to the research onion – the premise being that you start from the outside and peel each layer away until you reach the core. These layers are broken up into six main areas: research philosophy; research approach; research strategy; research choices; time horizons; and techniques and procedures. Each layer is explained below.
Research Philosophy
Research philosophy refers to the set of beliefs concerning the nature of the reality being investigated. It is generally examined in terms of ontology and epistemology. There is more detail on this in the article ‘Ontology and Epistemology: A Simple Explanation’, but here is a brief description of each:
- Epistemology: What Constitutes Valid Knowledge and How Can We Obtain It?
- Ontology: What Constitutes Reality and How Can We Understand Existence?
There are two main positions considered here, known as positivism and interpretivism. This underpins the qualitative versus quantitative debate, often referred to as “the scientist versus detective” debate. This is explained in more detail in the article ‘Positivism and Interpretivism: A Simple Explanation’.
Research Approach
This is referring to the approach that the researcher takes, which can largely be described as either inductive or deductive.
The deductive approach starts with an existing theory. The researcher develops a specific hypothesis (or hypotheses) from that theory and then collects data to test it. This is often described as moving from the general to the specific.
The inductive approach is the opposite. It starts with specific observations or data, and the researcher looks for patterns in order to develop a broader theory. This is often described as moving from the specific to the general. A third option, the abductive approach, moves back and forth between data and theory.
Typically, a deductive approach is associated with quantitative research and an inductive approach is associated with qualitative research.
There are some great texts on this, which will give you a more detailed explanation. A useful example is ‘Key Concepts in the Philosophy of Social Research’ by Malcolm Williams.
Research Strategy
The strategy layer of the research onion refers to how the researcher intends to carry out the work, i.e. what method of data collection will be used. You can read more about research method strategies in Creswell’s book ‘Research Design: Qualitative, Quantitative, and Mixed Methods Approaches‘.
Choices
The choices outlined in the research onion include the mono method, the mixed method, and the multi-method.
The mono-method involves using one research approach for the study. Next, the mixed-methods approach requires the use of two or more methods of research, and usually refers to the use of both a qualitative and a quantitative methodology. In the multi-method, a wider selection of methods is used. You can also read more about the use of mixed methods research in Creswell’s text, which is easy to understand and provides detailed explanations.
Time Horizons
The Time Horizon refers to the time frame within which the project is intended for completion. According to the research onion, there are two types of time horizons: cross-sectional and longitudinal.
The cross-sectional time horizon is when there is a pre-set time established for the collection of data. A longitudinal time horizon refers to the collection of data repeatedly over an extended period, for example when a person reaches a different age or different seasons throughout the year.
Data Collection and Analysis
The final layer of the research onion is techniques and procedures. This is the section where you should make explicit exactly how and why you are undertaking the research.
This can be referring to primary data (data collected first-hand for the research project), or secondary data (data that was collected by somebody else and subsequently published).
You will need to make your research design clear, with valid justifications for each stage. This provides a framework that includes the considerations that led to the appropriate methodology being adopted, the way in which the respondents were selected, and how the data will be analysed.
You will also cover research samples in this inner layer of the research onion. A sample is a representative segment of a larger population. In this instance, it is referring to the people who participated in your study. You will need to explain who was selected and why, supported by sampling theory, which you will find in most research methods textbooks. The reader will also want to know about your sample size.
Lastly, it is worthwhile addressing the ethics of your research in this last section of the research onion. This demonstrates that you have been an ethical researcher and that you comply with any regulations set upon you by your university.
So, that sums up the research onion. And in actual fact it sums up your overall methodology chapter for your research project! For more detail, it is a good idea to use some of the excellent research methods books available, such as Social Research Methods by Bryman and Research Methodology: A Step by Step Guide for Beginners by Kumar.
The YouTube video below also explains the research onion very clearly.
If you wish to cite any of the content in this post, please reference: Stainton, H. (2018) The research onion for beginners. Tourism Teacher. Available at: https://tourismteacher.com/research-onion-beginners/
The research onion: FAQs
Below are answers to some of the most common questions about the research onion.
What is the research onion?
The research onion is a model developed by Saunders, Lewis and Thornhill that shows the stages a researcher moves through when designing a methodology, from research philosophy on the outside to data collection and analysis at the core.
What are the six layers of the research onion?
The six layers are research philosophy, research approach, research strategy, methodological choice, time horizon, and techniques and procedures (data collection and analysis).
Who created the research onion?
The research onion was created by Mark Saunders, Philip Lewis and Adrian Thornhill and first appeared in their textbook Research Methods for Business Students in 2007.
What is the difference between a deductive and an inductive approach?
A deductive approach starts with theory and tests a hypothesis (general to specific), while an inductive approach starts with data and builds theory from it (specific to general).
How do I use the research onion in my dissertation?
Use the research onion to structure your methodology chapter, explaining and justifying your decisions at each layer, from your philosophy and approach through to your sampling, data collection, analysis and ethics.
The research onion: further reading
If you found this article helpful, you may also like these articles:
- Ontology and epistemology: a simple explanation
- Positivism and interpretivism: a simple explanation
- What is qualitative and quantitative research?
- Ethnography: a simple explanation
