Qualitative research interview guide: Types & techniques

Learn when to use structured, semi-structured, or unstructured interviews. Plus ethical considerations and sample size guidelines for your research

What are the best practices for conducting interviews in qualitative research?

Interviews in qualitative research are a primary tool for capturing the rich, detailed experiences of participants. They offer a window into the thoughts and perceptions that standard surveys simply cannot reach, making them essential for many academic studies. However, accessing meaningful data through interviews requires thoughtful planning—from designing open yet focused questions to addressing ethical concerns and managing personal bias. Researchers often grapple with questions about how many interviews are needed, how to organize the resulting data, and how to balance time constraints with a need for depth and clarity.

Let's explore practical steps and best practices to help you conduct interviews that yield insightful and well-organized findings.

How many interviews do I need for my qualitative research?

The magic number question has no magic answer. While quantitative and qualitative research rely on different methodologies, qualitative research focuses on depth and richness of data—making sample size decisions more nuanced.

The concept of "saturation" provides the most useful framework. Saturation occurs when additional interviews stop yielding new insights, themes, or codes. But how do you know when you'll reach it?

Several factors influence your required sample size:

• Research scope: Broader research questions typically require more interviews than narrowly focused ones.

• Participant homogeneity: More diverse participant pools generally need larger samples to capture varied perspectives.

• Interview structure: Highly structured interviews may reach saturation faster than unstructured conversations.

• Theoretical complexity: Research exploring complex theories often needs more data points.

Research by Guest et al. (2006) found that 80-90% of all themes were discoverable within the first 12 interviews, with saturation often occurring between 6-12 interviews for homogeneous groups. For more heterogeneous populations, Hagaman and Wutich (2017) suggest 16-24 interviews to identify common themes.

Practical approach to determining sample size:

1. Start with an initial estimate based on your research scope (6-10 for narrow, 15-20 for broader studies).

2. Build in flexibility to add participants if needed.

3. Analyze data concurrently with data collection.

4. Document when new codes/themes stop emerging.

5. Be prepared to justify your sample size decision in your methodology.

Remember that quality trumps quantity. A small sample of rich, well-conducted interviews often provides more valuable insights than a larger set of superficial conversations.

Best practices for ensuring ethical standards in qualitative interviews

Ethical interviewing isn't just about checking boxes—it's about respecting human dignity throughout your research. Beyond institutional review board requirements, ethical qualitative interviewing demands ongoing attention to participant wellbeing.

What are the core ethical principles for qualitative interviews?

• Informed consent: Participants must clearly understand what participation involves, how their data will be used, and their right to withdraw.

• Confidentiality: Protecting participant identities through anonymization and secure data handling.

• Minimizing harm: Being sensitive to emotional distress during interviews and providing appropriate support.

• Respect for autonomy: Allowing participants to skip questions or redirect the conversation.

• Reciprocity: Ensuring participants benefit in some way from their involvement.

How can you implement these principles practically?

Create clear, jargon-free consent forms that explain:

• Interview purpose and topics.

• Recording methods.

• Data storage procedures.

• How findings will be shared.

• Participant rights.

During interviews, practice ethical mindfulness by:

• Watching for signs of discomfort.

• Checking in regularly about continuing.

• Avoiding leading questions.

• Respecting cultural differences.

• Maintaining appropriate boundaries.

After interviews:

• Follow through on promised anonymization.

• Store data securely.

• Share findings with participants when appropriate.

• Delete recordings after transcription if promised.

Remember that ethical considerations evolve throughout your research. Regular reflection on your practices helps maintain the highest ethical standards while still gathering meaningful data.

Easy ways to organize and analyze qualitative interview data

Drowning in transcripts? You're not alone. The mountain of unstructured data from qualitative interviews can feel overwhelming, but systematic organization makes analysis manageable and insightful.

Before you begin analysis, set yourself up for success:

1. Transcribe consistently: Whether using verbatim transcription or focus-area summaries, maintain a consistent approach.

2. Establish a file naming convention: Include participant ID, date, and interview type (e.g., P01_042023_initial).

3. Create backup systems: Store copies in multiple secure locations.

4. Develop a coding approach: Decide between inductive (data-driven) or deductive (theory-driven) coding.

Practical techniques for organizing interview data:

• Color-coding: Assign colors to different themes or concepts for visual organization.

• Comment functions: Use document commenting tools to add notes without altering transcripts.

• Spreadsheet matrices: Create tables with participants in rows and themes in columns.

• Concept mapping: Visualize relationships between themes using mind-mapping tools.

Software options for different needs:

Budget Level	Recommended Tools	Best For
Free/Low-cost	QDA Miner Lite, RQDA, Taguette	Basic coding and theme identification
Mid-range	Dedoose, MAXQDA Base	Team collaboration, mixed methods
Professional	NVivo, Atlas.ti	Complex projects, advanced visualization

Analytical approaches to consider:

• Thematic analysis: Identifying patterns across interviews.

• Content analysis: Systematically categorizing content.

• Narrative analysis: Examining how stories are constructed.

• Discourse analysis: Analyzing language use and meaning.

Start analysis early—even after your first few interviews. This iterative approach helps refine your interview guide and identifies when you're approaching saturation.

Understanding structured, semi-structured, and unstructured interviews

Which interview format will best answer your research questions? The structure you choose significantly impacts the data you'll collect and how you'll analyze it.

Each interview format exists on a continuum of researcher control versus participant freedom:

Structured interviews provide the highest level of standardization:

• Fixed questions asked in the same order.

• Limited probing or follow-up.

• Often include predetermined response categories.

• Produce more easily comparable data.

• Work well when testing specific hypotheses.

When to use structured interviews:

• Comparing responses across participants.

• Validating existing theories.

• Working with large sample sizes.

• When interviewers have limited training.

Semi-structured interviews balance flexibility with focus:

• Pre-planned questions serve as a guide.

• Allow for probing and follow-up questions.

• Adjust question order based on conversation flow.

• Combine comparable data with rich descriptions.

• Support both inductive and deductive approaches.

When to use semi-structured interviews:

• Exploring complex topics with some existing understanding.

• Balancing participant voice with research focus.

• Working with moderately sized samples.

• When consistency across multiple interviewers is needed.

Unstructured interviews maximize discovery and depth:

• Begin with a broad topic rather than specific questions.

• Follow participant's lead in conversation.

• Minimize researcher direction.

• Generate rich, detailed narratives.

• Support inductive theory building.

When to use unstructured interviews:

• Exploring entirely new phenomena.

• Prioritizing participant perspectives.

• Working with small samples.

• When researchers have strong interviewing skills.

Most qualitative research uses semi-structured interviews, which provide the best balance between consistency and discovery. However, consider mixing approaches—starting with unstructured exploration before moving to more focused questions can yield particularly rich insights.

Final Thoughts

Conducting effective qualitative interviews is both an art and a science. Throughout this exploration, we've unpacked the nuanced strategies that transform raw conversations into meaningful research insights. From carefully crafting interview questions to navigating ethical considerations and managing potential biases, successful qualitative interviewing requires thoughtful preparation, active listening, and rigorous analytical skills.

The journey of qualitative research is ultimately about understanding human experiences in their richness and complexity. Each interview represents an opportunity to uncover deeper perspectives that quantitative methods might miss. By approaching interviews with curiosity, respect, and methodological precision, researchers can generate profound insights that illuminate complex social phenomena.

At Highlight, we recognize that robust research methodologies are the foundation of meaningful product development and consumer understanding. Just as a skilled interviewer carefully extracts nuanced insights, our approach centers on helping brands connect more authentically with the stories and experiences that drive consumer behavior.