Having a clear understanding of what comprises a doctoral thesis is essential for effectively planning and structuring your research. It will help you decide what you are going to write and how to shape the whole thesis.
Note that not every thesis follows exactly the same structure. Conventions can vary between disciplines, while each specific area of research may call for slightly different approaches, flow and presentation. Reading widely around your specific area will give you an idea of the most common, tried-and-tested formats in your field; and when you start writing, you will also discover the best, most sensible ways of presenting your research.
Whatever format you eventually decide on, these are components that every good doctoral thesis should incorporate:
Your research question or hypothesis
Many researchers use actual questions or statements to guide their research, but this part of your thesis does not always have to be a literal question. It is a declaration of what exactly you intend to explore, investigate or find out in your research. Some PhD candidates may work with a very specific hypothesis that they then prove/disprove and discuss through their thesis – for example, “Regular physical exercise improves the quality of sleep in teenagers”. Other researchers may begin with more open-ended questions or premises, such as, “How does regular physical exercise affect the physical and mental health of teenagers?”
The main body of your research is then shaped around how you answer these questions/hypotheses (what literature/theoretical frameworks and methodological approaches you employ) and what you find from your research (your analysis and discussion).
Sometimes also known as a ‘critical context’, a literature review demonstrates your understanding and awareness of the existing research and writing in your field. You can include a discussion and overview of the prominent debates around your subject to set the context for your research, and to locate where and how your work will extend or contribute to the current canon of knowledge.
Use the literature review to identify gaps in the existing research or to problematise current/prominent theories. Explore the merits and limits of the literature, debates and arguments that you plan to engage with. Then, following these discussions, you can move to assert your newly formulated research questions and/or hypotheses, and to address them through the rest of your research.
Including some discussion about the methodological decisions you have taken towards your research is very important for explaining how you have conducted your research. For some projects, the ontological and epistemological basis informing the study may play a very significant role in the way that data are collected, analysed and discussed, and it is important that these considerations and perspectives are accounted for.
Remember that a PhD does not just assess what you find out in your research, but how you go about obtaining these results, how you analyse them and how you draw the conclusions that you do. Declaring your methodological approaches and methods/practices is crucial for demonstrating your clear understanding of and justification for why you have done this research in the ways you have chosen.
Do note that the ‘methods’ section of a thesis can look very different between theses. Some studies require a more extensive discussion of the methodological approaches used throughout the research, while others may only include a brief outline of a relatively straightforward method.
Analysis and/or discussion
In some disciplines, the analysis and discussion chapters are separated from each other; in others, analysis and discussion are written in tandem with each other, and chapters are distinguished by theme rather than by process.
However you choose to present these chapters, the analysis and discussion is what forms the heart of your research. This is where your unique, original findings and arguments are discussed and presented. Where the two previous sections of the literature review and methodology ‘set the scene’ for your research, these sections are the main act.
It is in these sections that you deal directly with the data or sources you are working with. The theory and literature that you are engaging with, the methodological approaches that you are using and your close examination of the data all come together here as you work towards answering the research questions you started with, and to develop the original knowledge that you intend to contribute to the field.
Thinking outside the box
Finally, be aware that not all PhD research will follow exactly the same structure. Some theses, such as those in arts-, media- or humanities-based disciplines, or those containing a strong practice-based component, can take unusual forms and even include creative media such as plays, novels, films or video games.
If you are considering an alternative approach, work with your supervisor(s) to find the best ways for presenting your research. Also, bear in mind that even if the format or structure of your doctoral research is unconventional, you would still be expected to somehow incorporate most of the elements discussed above to demonstrate your research skills and understanding of the prominent debates, literature, theory and methodologies in your subject.