Qualitative vs quantitative research
The real difference between qualitative and quantitative dissertation research, and how to choose based on your question rather than your comfort zone.
8 min read · Reviewed 2026 · Written and reviewed by Chris McGarrigle
The choice is not about whether you like numbers. It is about what kind of claim your research question demands, and what kind of evidence can support that claim.
Quantitative work measures and compares. Qualitative work interprets meaning. Mixed methods does both, deliberately, and costs roughly twice as much time.
Match the design to the claim
If your question asks how much, how many, or whether a relationship holds across a population, you need measurement, a defensible sample and statistical analysis.
If your question asks how people experience, interpret or justify something, you need depth: interviews, focus groups, documents or observation, analysed for meaning.
What counts as quality differs
Quantitative quality is argued through validity, reliability, sampling and statistical power. Qualitative quality is argued through credibility, transferability, dependability and confirmability — with an audit trail and reflexivity about your own position.
Applying the wrong quality criteria to your design is a reliable way to lose marks. Do not promise generalisability from eight interviews.
Mixed methods, honestly
Mixed methods is legitimate but must be justified by the question, not by indecision. Say explicitly whether the strands run sequentially or concurrently, which one leads, and at what point you integrate the findings.
Common mistakes
- Choosing a survey because it feels quicker, then having nothing to interpret.
- Claiming generalisability from a small qualitative sample.
- Running both strands without explaining how they integrate.
- Letting the method drive the question instead of the reverse.
Try this: Write both versions
- Draft a one-paragraph quantitative design for your question.
- Draft a one-paragraph qualitative design for the same question.
- For each, note what you could claim and what you could not.
- Choose the one whose claims match what your question promises.
Do it in SuperDiss
Work through philosophy, approach and design — and be able to defend each choice.
Open the Methodology LabStudents also ask
- What is the difference between qualitative and quantitative research?
- Quantitative research measures how much, how many or how strongly variables relate, using numeric data and statistical analysis. Qualitative research explores how and why people experience or interpret something, using interviews, observation or documents analysed for meaning.
- Which should I use for my dissertation?
- Let the research question decide. Questions beginning 'how do people experience' point to qualitative work; questions about prevalence, difference or relationship point to quantitative work.
- Is mixed methods harder?
- Usually yes, at undergraduate and master's level, because you must justify and execute two designs and integrate the findings. Only choose it when one dataset genuinely cannot answer the question.
Related research: design the methodology
Choose philosophy, approach, sampling and ethics you can defend in the viva.
How to choose a methodology
A decision path from research question to methodology, plus how to write the justification examiners are looking for.
Research philosophy explained: ontology, epistemology and axiology
A clear introduction to research philosophy for dissertations: ontology, epistemology and axiology, and how they shape your methodology choices.
How to get ethical approval
What ethics committees actually look for, the documents you need, and the mistakes that cause applications to be returned.
Continue your dissertation journey
- How to choose a methodology
- The research onion explained
- Research philosophy explained: ontology, epistemology and axiology
- Interpretivism vs positivism: which fits your dissertation?
- Sampling explained
Browse every guide in research methodology.
Read next
How to choose a methodology
A decision path from research question to methodology, plus how to write the justification examiners are looking for.
The research onion explained
The research onion as a decision-making tool rather than a diagram to copy: what each layer asks and how the layers constrain each other.
This guide is general educational content. Your institution's regulations, handbook and supervisor's instructions always take precedence. Where a named framework is mentioned, consult the original source text rather than relying on this summary.