The Ultimate Guide to In-Depth Interviews
Learn how to conduct powerful one-on-one interviews to uncover the deep insights, motivations, and pain points that drive customer behavior.
While surveys can tell you what people do, interviews tell you why they do it. Mastering this skill is a superpower for any product manager, marketer, or designer. For a broader overview, see our complete Guide to Qualitative Research.
An in-depth interview (IDI) is more than a conversation; it's a systematic method for uncovering deep insights into someone's world.
It's the single most powerful tool for understanding the 'why' behind a user's behavior, needs, and frustrations.
This guide provides an actionable framework to plan, conduct, and analyze interviews like a professional researcher.
When to Use In-Depth Interviews
Interviews are your go-to method for depth and context. They are ideal for exploratory and generative research phases.
When you're at the beginning of a project and need to understand the landscape, user needs, and opportunities.
To understand a user's end-to-end process for accomplishing a task, including their tools, pain points, and emotions.
To gather the deep, empathetic insights about goals, motivations, and frustrations needed to create rich user personas.
The one-on-one format provides the privacy and trust needed to discuss sensitive subjects that wouldn't work in a group setting.
Types of Interviews
While there are several types, the semi-structured interview is the most common and effective for most business research.
Structuring a 45-Minute Interview
A well-structured interview has a clear beginning, middle, and end. Follow this simple three-part structure.
The Introduction & Warm-Up (5 mins)
Build rapport and set expectations. This is crucial for making the participant feel comfortable.
- Thank them for their time and explain the purpose of the session (to learn from them).
- Assure them there are no right or wrong answers and that you didn't design what you're discussing.
- Ask for permission to record the session.
- Start with easy, non-threatening questions ('Tell me about your role...').
The Main Body: Deep Dive (30-40 mins)
This is the core of the interview, organized by themes from your discussion guide.
- Use open-ended questions to explore past behaviors ('Walk me through the last time you...').
- Follow the 'Funnel' technique: start broad and then get more specific.
- Listen more than you talk. Use silence to encourage the participant to elaborate.
- Use active listening cues ('So what I'm hearing is...') to confirm understanding.
The Cool-Down & Wrap-Up (5 mins)
End the interview on a positive note and provide a final opportunity for feedback.
- Ask if there is anything else they'd like to share that you haven't asked about.
- Thank them again for their valuable insights.
- Confirm how and when they will receive their incentive.
Asking Effective Questions
The quality of your insights is directly tied to the quality of your questions.
Good Example
"Tell me about the last time you bought a flight online."
Bad Example
"Would you use a feature that let you book flights with crypto?"
Good Example
"How do you currently manage your team's budget?"
Bad Example
"Is managing your team's budget difficult?"
Good Example
"You mentioned that was 'frustrating.' Can you tell me more about what was frustrating about it?"
Bad Example
"Okay, got it."
The Art of Moderation
A great moderator makes the participant feel like an expert and a partner in the conversation.
Listen more than you talk. Your job is to listen, not to pontificate. Aim for an 80/20 split of participant talking vs. you talking.
Embrace silence. When a participant finishes a thought, wait a few seconds before you jump in. They will often fill the silence with more valuable information.
Be neutral. Don't praise or criticize their answers. Phrases like 'That's great!' can introduce bias. Instead, use neutral affirmations like 'Okay' or 'I see.'
Be comfortable with 'I don't know.' Not every participant will have an answer for every question, and that's okay. Don't pressure them.
Common Interview Pitfalls
Avoid these common mistakes to protect the integrity of your research.
'Don't you think this is easier?' This pushes the user to agree with you.
Solution: Ask neutral questions: 'How would you describe that process?'
They will want to be nice and won't give you honest, critical feedback.
Solution: Recruit participants who have no personal connection to you or your project.
Switching from 'learning mode' to 'selling mode'. This shuts down honest feedback.
Solution: Your goal is to learn about their problem, not to convince them to use your solution.
When a user asks 'What does this button do?', don't answer directly. This is a key insight.
Solution: Turn the question back to them: 'What would you expect it to do?'
Interviewing FAQs
Common questions about planning and conducting in-depth interviews.
Ready to Start Interviewing?
Download our free Interview Starter Kit, featuring a discussion guide template, a recruitment screener, and a consent form.