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The research onion for beginners

Today I will explain the research onion in simple terms. This builds on from my last post, where I introduced you to the concept of research philosophy, giving the simple analogy of a tree which demonstrated how philosophy is inherently linked to research design. 

What is the research onion?

The research onion was developed by Saunders et al in 2007 to describe the stages through which a researcher must pass when developing an effective methodology. Just as I previously explained, 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.

research onion

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. I will explain what each layer means below.

Research onion

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. I have provided more detail on this in my post- Ontology and Epistemology: A Simple Explanation’, but for now I will provide a brief description of each as follows:

  • 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. I explain exactly what all of this means in my post- ‘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.

Research onion

The deductive approach starts small and gets bigger. It starts with a specific hypothesis or hypotheses that have been developed based on information or patterns that have been observed by the researcher. It then seeks to test this hypothesis and develop a broader theory from it.

The inductive approach is the opposite. It starts with a broad theory and then focuses later on the smaller, more specific details. This is sometimes referred to as a move from the specific to the general.

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. One of my favourites is ‘Key Concepts in the Philosophy of Social Research’ by Malcolm Williams, which I used a lot when writing my PhD thesis. 

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 Cresswell’s book ‘Research Design: Qualitative, Quantitative, and Mixed Methods Approaches.


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 required 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 Cresswell’s text, which is personally one of my favourites- it’s 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.

Research onion

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! I have a number of posts covering each of the areas mentioned in the research onion further, so read on should you require further guidance. I also recommend that you use some of the excellent research methods books available to you- I recommend Social Research Methods by Bryman and Research Methodology: A Step by Step Guide for Beginners by Kumar.

Lastly, I have also included a handy YouTube video below that explains the research onion very clearly (I’ll get round to making my own one day).

If you wish to cite any of the content in the post please reference ‘Stainton, Hayley. (2018) Lifeasabutterfly.’