Questionnaire vs Interview: When to Use Each (and How to Combine Them)

What Is a Questionnaire Interview?

A questionnaire interview usually means one of two things, and both are common in research and business:

• An interview run from a questionnaire. A researcher or recruiter follows a fixed set of questions — the questionnaire is the script. This is the classic structured or semi-structured interview used in user research, hiring, and field studies.

• A mixed-methods design. You collect a written questionnaire from many people, then interview a smaller subset to explain the "why" behind the numbers.

In both cases the questionnaire brings consistency (everyone is asked the same thing), while the interview brings depth (you can probe, clarify, and hear the story). That combination is why the "questionnaire interview" shows up everywhere from PhD theses to product discovery.

Questionnaire vs Interview

They are not rivals — they solve different problems. Use this table to pick, or to decide where each belongs in one project.

The takeaway: a questionnaire tells you how many; an interview tells you why. The strongest research plans use both.

6 Reasons to Use Both (Mixed Methods)

1. Numbers need a story: A 60% churn rate is a headline; an interview explains what made people leave.

2. Test what you heard: Interview insights are richer but small-n. A follow-up questionnaire checks if they hold at scale.

3. Screen then dig: Send a questionnaire to 500 people, interview the 20 most interesting responses.

4. Reduce bias: Quant data balances interviewer influence; qual data catches what closed questions miss.

5. Stakeholder buy-in: Execs love a chart; teams love a quote. Mixed methods persuade both.

6. Cheaper depth: You get 80% of the insight of 50 interviews by interviewing 8 after a survey.

30+ Interview Questionnaire Questions

1. Customer Discovery Interview

1. Walk me through the last time you used a product like ours.

Probe: What triggered the need, and what almost stopped you?

2. What did you try before finding us, and why did it fall short?

3. Describe the moment our product clicked for you.

Probe: Was it a feature, a feeling, or a person who helped?

4. If you could change one thing about the experience, what would it be?

5. Who else is involved in the decision to keep or drop us?

6. How would your week be different without this product?

2. User Research / UX

7. Show me how you currently solve this task today.

Probe: Where do you get stuck or switch tools?

8.What were you expecting to happen when you tapped that button?

9. Tell me about a time the product surprised you — good or bad.

10. Which step felt like the most effort, and why?

11. How does this fit into the rest of your workflow?

3. Employee Exit Interview

12. What was the main reason you started looking elsewhere?

Probe: When did that reason first appear?

13.Was there a moment you considered staying? What changed?

14. What did you enjoy most, and what would you change for your replacement?

15. How clear were your goals and growth path here?

16. What would make this a place you'd recommend to a friend?

4. Job Screening Interview

17. Tell me about a project you're proud of and your exact role in it.

Probe: What was hard, and how did you handle it?

18.Describe a time you disagreed with a teammate — what happened next?

19. How do you prefer to receive feedback?

20. What kind of work drains you, and what energizes you?

21. Where do you want to be in two years, and how does this role fit?

5. Academic / Field Research

22. How did you first become involved with this community or practice?

Probe: Who introduced you, and when?

23.In your own words, how would you explain this phenomenon?

24. What changed in your view over the years, and why?

25. Can you describe a typical day related to your experience?

26. What do outsiders usually misunderstand about this?

6. Market Research Interview

27. How do you currently decide between brands in this category?

Probe: Which source do you trust most?

28.What would make you switch to a new option tomorrow?

29. Which claim from a brand has ever felt dishonest to you?

30. Describe the ideal version of this product — what's missing today?

7 Rules for Writing a Good Interview Questionnaire

1. Start with 5–8 questions: Enough to cover themes, short enough to finish in 20–30 minutes. More than 12 and quality drops.

2. Group by theme: Cluster questions (background → behavior → attitude → wish) so the flow feels natural, not random.

3. Use plain language: Write like you talk. Avoid jargon, double negatives, and "official" phrasing that makes people polite, not honest.

4. One probe per question: Add a "why / example?" follow-up so you never leave an interesting answer unexplored.

5. Open, not leading: "What did you think?" beats "Did you like it?" — the second plants the answer.

6. Mix types: Blend behavioral ("tell me about a time"), opinion ("what matters most"), and hypothetical ("if money were no object") questions.

7. Pilot once: Run it with one person, time it, and cut anything confusing. A 10-minute pilot saves hours of bad data.

5 Mistakes to Avoid

1. The yes/no trap: Closed questions waste the interview. If you only need yes/no, that belongs in the questionnaire.

2. Leading the witness: "You found that annoying, right?" pushes answers. Stay neutral and curious.

3. Too long: Fatigue produces shallow answers. Respect the 30-minute ceiling.

4. No recording consent: Always ask permission to record or note-take — it's both ethical and legal.

5. Skipping the questionnaire: Pure interviews without a screening survey waste time on the wrong people.

WorkflowHow to Run a Questionnaire + Interview Project

Two proven sequences — pick based on whether you're exploring or confirming:

1. Questionnaire first (confirm at scale): Send a survey to a large sample, segment the results, then interview 8–12 standout respondents to explain the patterns.

2. Interview first (explore, then test): Run 5–8 interviews to surface themes, then build a questionnaire to measure how common those themes are across a bigger group.

3. Wrap with a short survey: After each interview, send a 2–3 question thank-you survey to capture a quick rating while the conversation is fresh.

4. Analyze together: Quantify the survey in charts; code the interviews for quotes; let each explain the other in your report.

Conclusion

A questionnaire interview is at its best when it stops being either/or. Use the questionnaire to reach the many and standardize the questions; use the interview to reach the few and understand the why. The 30+ questions above cover customer discovery, UX, exit, hiring, academic, and market research, so you can lift a prompt for almost any project.

Keep interviews short, open, and well-probed, and let a questionnaire do the screening and scaling. When you're ready to build that questionnaire, SurveyMars gives you open-ended questions, logic, mobile preview, and free sharing by link, QR, or embed. Start from the SurveyMars and launch in minutes.

FAQs

Q1: What is a questionnaire interview?

A1: A "questionnaire interview" usually means one of two things: (1) a structured or semi-structured interview where the interviewer follows a fixed set of questions (the questionnaire acts as the script), or (2) a research design that pairs a written questionnaire with follow-up interviews. In both, the questionnaire provides consistency while the interview adds depth.

Q2: What is the difference between a questionnaire and an interview?

A2: A questionnaire is a written set of questions answered by the respondent (self-administered or online), built for scale and standardization. An interview is a live, two-way conversation led by an interviewer, built for depth and follow-up. Questionnaires reach hundreds cheaply; interviews reach a few people deeply.

Q3: When should I use an interview instead of a questionnaire?

A3: Use an interview when the topic is complex, sensitive, exploratory, or when you need to probe "why." Use a questionnaire when you need comparable data from a large sample, fast turnaround, or statistical analysis. Most strong studies use both in sequence.

Q4: How do I write a good interview questionnaire?

A4: Start with 5–8 open questions, group them by theme, use plain language, add one probe per question (e.g., "Can you give an example?"), and pilot with one person. Keep it short enough to finish in 20–30 minutes.

Q5: Can SurveyMars be used for interviews?

A5: SurveyMars is built for questionnaires, but it supports interview-style research in two ways: share the questionnaire as a script the interviewer reads aloud and records notes against, or send it as a link for a short pre- or post-interview survey. Open-ended question types capture the qualitative answers.

Q6: What is the best order: questionnaire first or interview first?

A6: It depends. Run the questionnaire first when you need to screen or quantify, then interview a subset for depth. Run interviews first when the topic is unexplored, then build a questionnaire to test what you learned at scale. Both are valid mixed-methods flows.