Choosing between qualitative and quantitative research — or combining them — is one of the most important decisions in your dissertation. Each approach answers different kinds of question and uses different methods. This complete UK guide explains the difference, when to use each, what mixed methods means, and how your research questions should drive the choice.
The Core Difference
Quantitative research deals with numbers — measuring, counting and testing relationships statistically. Qualitative research deals with meaning — exploring experiences, views and contexts through words. One asks “how much/how many”; the other asks “how/why”.
When to Use Quantitative
Use quantitative methods when you want to measure, compare or test hypotheses across a large sample — surveys, experiments, statistical analysis. It suits questions about prevalence, relationships and cause and effect.
When to Use Qualitative
Use qualitative methods when you want to understand experiences, meanings or processes in depth — interviews, focus groups, observation, thematic analysis. It suits exploratory questions where rich detail matters more than numbers.
Mixed Methods
Mixed methods combine both — for example, a survey followed by interviews — to gain both breadth and depth. It is powerful but more demanding, requiring you to justify and integrate both strands.
Let Your Questions Decide
The choice should flow from your research questions, not personal preference. Questions about “how many” point to quantitative; questions about “why” or “how” point to qualitative. See our research question guide.
Common Mistakes and Tips
✓ Choosing a method before the questions.
✓ Using qualitative data to make statistical claims.
✓ Treating mixed methods as just “doing both”.
✓ No justification. Tip: let your research questions drive the choice and justify it in your methodology.
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Frequently Asked Questions
What is the difference between qualitative and quantitative research?
Quantitative deals with numbers and measurement; qualitative deals with meaning, experiences and words.
When should I use quantitative research?
When measuring, comparing or testing hypotheses across a large sample.
When should I use qualitative research?
When exploring experiences, meanings or processes in depth.
What are mixed methods?
An approach combining qualitative and quantitative methods for breadth and depth.
Which approach is better?
Neither — the right one depends on your research questions.
Can I combine both?
Yes — mixed methods, if justified and properly integrated.
What methods are quantitative?
Surveys, experiments and statistical analysis.
What methods are qualitative?
Interviews, focus groups, observation and thematic analysis.
Related Study Guides
How to Write a Methodology • How to Write a Research Question • How to Do a Thematic Analysis • How to Write a Dissertation
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