Qualitative research investigates meanings, experiences and processes; quantitative research analyses measured variables and numerical relationships. Choose the approach that answers your dissertation question, then decide how to collect and analyse the data. Mixed methods combines both approaches with an explicit plan for integrating their findings. Neither a questionnaire nor an interview determines the whole design on its own.
What is the practical difference?
| Decision | Qualitative approach | Quantitative approach |
|---|---|---|
| Aim | Understand experience and context | Estimate frequency, differences or relationships |
| Possible data | Interviews, observations, documents | Scale scores, measurements, administrative records |
| Analysis | An appropriate interpretive approach, such as thematic analysis | Descriptive and, where justified, inferential statistics |
| Key limitation | Context and interpretive decisions | Measurement, sampling and statistical assumptions |
The University of Delaware research guide compares research processes. These are typical possibilities rather than rigid boundaries. Qualitative analysis requires a documented method; quantitative results also need interpretation.
How does one topic produce different questions?
Consider students combining paid employment with university study. The following examples are hypothetical planning exercises, not completed research or reported findings.
Qualitative: How do first-year students describe conflicts between work schedules and exam preparation? You might plan semi-structured interviews with students who have relevant experience. Explain recruitment, recording, transcription and the analytical approach. Counting repeated words alone is not a thematic analysis.
Quantitative: What is the relationship between weekly working hours and academic-stress scores in a defined student population? Specify the time period, measurement of working hours and suitability of the stress instrument. Plan analysis around the variables and the assumptions of the selected method.
Mixed methods: What numerical pattern appears, and how do selected students explain contrasting experiences? Interviews might follow a survey, but explain how participants are selected and how both sets of findings will be integrated. Two unrelated analyses do not automatically form a convincing mixed-methods design.
How do you choose participants and sample size?
Define the population, eligibility criteria and recruitment method. A large convenience sample is not automatically representative. Random sampling and random assignment to experimental conditions address different problems.
For quantitative work, justify sample size through the estimation or testing goal, variability, desired precision or statistical power. For qualitative work, justify scope, diversity of experience, approach and analytical depth. There is no universal minimum suitable for every dissertation. Onwuegbuzie and Collins discuss sampling decisions in mixed-methods designs.
Do you need hypotheses, and can you claim causation?
A hypothesis suits a reasoned, testable expectation about variables. Some descriptive quantitative projects use research questions instead. Qualitative questions are often open-ended and should fit the chosen approach.
A one-off survey showing a relationship between work and stress does not establish that work caused stress. Other variables or reverse direction may explain the pattern. Interviews with selected participants likewise do not estimate how common an experience is across the whole population. Keep conclusions within the design’s limits.
What belongs in the methods chapter?
Describe the question, rationale, setting, sampling, instruments, data collection and analysis. Explain participant information, consent, data protection and required approvals under your institution’s rules. Replacing names may not fully anonymise distinctive accounts. Discuss measurement and recruitment limitations and the researcher’s interpretive role.
Before collecting anything, complete the worksheet and discuss it with your supervisor. If you cannot explain how the data will be analysed, revise the design before distributing the questionnaire.
FAQ
Is qualitative research easier?
Not necessarily. Recruitment, transcription and rigorous interpretation can require substantial time.
Is every questionnaire quantitative?
No. It can collect numerical or open-text data. The question and analysis determine the approach.
How many participants do I need?
Justify the number for your specific design and aim. A universal dissertation-wide minimum is not defensible.
Does correlation prove causation?
No. A causal claim requires an appropriate design and further justification.
Downloadable worksheet
Related guides
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