Why do some interviews produce rich, quotable data while others yield short answers that say little? Usually the difference was decided before the recorder was switched on: in the interview guide, the order of questions, the follow-up prompts and the setting. Semi-structured interviews give you flexibility, but that flexibility only works when it rests on careful preparation.
This article is part of our guide How to Write a Master’s Thesis by the Mastermind PhD team and relates to our Survey & Questionnaire Design service. Sources last checked: November 2026.
This guide explains when semi-structured interviews suit a thesis, how to design an interview guide in five phases, how many interviews to plan, and how to record, transcribe and report them so that examiners can trust your data.
What are semi-structured interviews? They are qualitative interviews that follow a prepared guide of open-ended main questions on predetermined themes, while allowing the interviewer to change the order, ask follow-up questions and probe for detail. They combine comparability across participants with the flexibility to explore each participant’s experience in depth.
When should you use semi-structured interviews?
Use them when your research question asks how or why people experience, understand or decide something, and when you already know enough about the topic to define themes. They suit questions such as “How do novice teachers experience their first year of inclusive classrooms?” or “Why do small firms delay digital adoption?”
They are less suitable when you need to measure prevalence or test relationships between variables (use a survey), when the topic is so new that any predefined structure would constrain participants (consider unstructured or narrative interviews), or when group interaction is part of the phenomenon (consider focus groups).
How do you design the interview guide? Five phases
Kallio and colleagues (2016), in a systematic methodological review, describe five phases for developing a semi-structured interview guide:
- Identify the prerequisites. Confirm that semi-structured interviews fit the research question and that participants can talk about the topic.
- Use previous knowledge. Draw themes from the literature and, where relevant, from your own professional understanding of the field.
- Formulate the preliminary guide. Write main questions for each theme, plus follow-up questions and probes.
- Pilot test the guide. Try it internally with your supervisor, with experts, or in a field test with one or two participants from the target group.
- Present the complete guide. Include the final version in an appendix and explain its development in the methodology.
A typical guide has 5 to 10 main questions for an interview of 45 to 60 minutes. More than that tends to turn the conversation into a questionnaire read aloud.
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Which types of questions should the guide include?
| Question type | Purpose | Example |
|---|---|---|
| Opening question | Build rapport, start with something easy | “Could you tell me about your role and how long you have been in it?” |
| Main (core) questions | Cover each theme with open wording | “How would you describe a typical week of supervising students?” |
| Follow-up questions | Develop a point the participant raised | “You mentioned workload. What does that look like in practice?” |
| Probes | Ask for detail, examples or clarification | “Can you give me an example?” “What happened next?” |
| Closing question | Allow anything missed | “Is there anything else you think I should know?” |
Avoid leading questions (“Don’t you think the policy failed?”), double questions (“How did you feel and what did you do?”) and jargon participants may not share. DeJonckheere and Vaughn (2019) describe semi-structured interviewing as a balance between relationship and rigor, so a common approach is to move from broad, easy questions to more specific ones and to leave sensitive topics until rapport is established.
How many interviews do you need?
There is no fixed number. In Guest, Bunce and Johnson’s (2006) analysis of 60 interviews with a fairly homogeneous group, most of the codes they eventually identified had appeared within the first 12 interviews. Malterud, Siersma and Guassora (2016) propose the concept of information power: the more focused the aim, the more specific the participants’ experience, the stronger the use of theory and the higher the quality of dialogue, the fewer participants are needed.
For a master’s thesis built on semi-structured interviews, justify your number by the study’s aim, the specificity of the sample and the planned analysis, not by convention alone, and agree a provisional target with your supervisor before ethics approval. Plan the analysis alongside data collection so that you can judge when new interviews stop adding new insight.
How should you record the interviews?
- Consent: obtain written consent for recording, explain how recordings will be stored and when they will be deleted, and confirm consent verbally at the start of the recording.
- Equipment: use two recording devices for in-person interviews, test them in the room beforehand, and choose a quiet place.
- Online interviews: check the platform’s recording and storage settings and whether your university approves it for research data. Ask participants to use headphones if possible.
- Field notes: immediately after each interview, write brief notes on context, nonverbal cues and initial impressions.
- Data protection: store recordings on university-approved, password-protected storage, in line with your ethics approval and applicable data protection law.
How do you transcribe semi-structured interviews?
Decide the level of detail before you start:
- Verbatim transcription records every word, including hesitations, repetitions and fillers. It suits analyses where the way something is said matters.
- Intelligent (clean) verbatim removes fillers and false starts while keeping meaning and wording. It suits most thematic analyses.
Set conventions and apply them consistently: speaker labels (for example “I” and “P07”), time stamps at regular intervals, marks for inaudible passages and pauses, and how you indicate laughter or emphasis. Transcription takes considerably longer than the recording itself, so budget time accordingly.
Automatic transcription tools can save time but make errors with accents, technical terms and overlapping speech. Check every transcript against the audio, and confirm that the tool complies with your ethics approval, since some upload recordings to external servers.
Anonymize as you go: replace names with codes, remove or generalize identifying details (workplace, small town, unusual job title) and keep the key linking codes to identities in a separate, secured file.
How do you report the interviews in the thesis?
The methodology chapter should state the type of interview and why it fits the question; how the guide was developed and piloted; the sampling strategy and number of participants with the justification; the mode, duration and dates of the interviews; recording, transcription conventions and anonymization; and the analytic approach. For thematic analysis, Braun and Clarke (2006) describe six phases, from familiarization with the data to producing the report. Put the full interview guide in an appendix.
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Frequently asked questions
What is the difference between structured and semi-structured interviews?
Structured interviews ask identical questions in a fixed order, often with closed responses. Semi-structured interviews use a guide but allow the interviewer to change the order, follow up and probe.
How long should each interview be?
Most last between 30 and 90 minutes. Pilot the guide to estimate the duration and tell participants in advance.
Can I conduct the interviews in another language and translate?
Yes. Transcribe in the original language, translate the excerpts you quote or the full transcripts, explain the translation process and consider back-translation for key terms.
Should participants check their transcripts?
Some researchers offer transcript review to improve accuracy. It is optional, adds time and should be described in the methodology if used.
Do I need ethics approval for semi-structured interviews?
Almost always, because they involve human participants and recorded personal data. Submit the guide, consent form and data management plan with your application.
Sources
- Kallio, H., Pietilä, A.-M., Johnson, M., & Kangasniemi, M. (2016). Systematic methodological review: Developing a framework for a qualitative semi-structured interview guide. Journal of Advanced Nursing, 72(12), 2954–2965. https://doi.org/10.1111/jan.13031
- DeJonckheere, M., & Vaughn, L. M. (2019). Semistructured interviewing in primary care research: A balance of relationship and rigour. Family Medicine and Community Health, 7(2), e000057. https://doi.org/10.1136/fmch-2018-000057
- Guest, G., Bunce, A., & Johnson, L. (2006). How many interviews are enough? An experiment with data saturation and variability. Field Methods, 18(1), 59–82. https://doi.org/10.1177/1525822X05279903
- Malterud, K., Siersma, V. D., & Guassora, A. D. (2016). Sample size in qualitative interview studies: Guided by information power. Qualitative Health Research, 26(13), 1753–1760. https://doi.org/10.1177/1049732315617444
- Braun, V., & Clarke, V. (2006). Using thematic analysis in psychology. Qualitative Research in Psychology, 3(2), 77–101. https://doi.org/10.1191/1478088706qp063oa
- Kvale, S., & Brinkmann, S. (2015). InterViews: Learning the Craft of Qualitative Research Interviewing (3rd ed.). SAGE.
Sources last checked: November 2026. This article is general educational guidance and does not replace your university regulations or your supervisor’s instructions. How we prepare our content.