UX/UI Design, A to Z ┃ 1.10 User Interviews (Part 2): Digging Beneath the Answer

Welcome back — always :)

The best question in an interview is rarely one you wrote down beforehand. It's the one you find inside what the participant just said.

A participant tells you the checkout was confusing. You write it down, nod, move to your next scripted question — and you've just walked past the interview.

Confusing how? What were you looking at? What did you do next? The answer they gave you was a door. Good interviewing is knowing to open it.

First, a Word About What You're Doing

Before any technique: the goal of the Discover phase is not to nail down one true "root cause."

It's to build a broad understanding — who these people are, what they're trying to do, how they behave now, what problems and needs they carry. What someone tells you in an interview is a valuable clue, but it needs to be checked against other participants, against observation, and against your data.

Keep that in mind as you read what follows. The techniques below are for going deeper, not for arriving at a single answer.

The 5 Whys: Going One Layer Down

The 5 Whys is a probing technique: take one answer, then keep asking what's behind it. It's useful for finding the motivation, value, or context sitting underneath the first goal or complaint someone names.

The name says five, but five isn't a rule. Three might be enough. Sometimes you need to go further. What matters isn't hitting a number — it's whether you understand enough to answer your research question.

Here's the classic example:

Starting point: "I want to own my own business."

What just happened

The stated goal was starting a business. Five questions later, the real value underneath it was protecting family time. Those two things lead to completely different designs.

But note carefully — that's a hypothesis drawn from one person's account. Before it becomes a design direction, it needs support from somewhere else.

Where it comes from

The 5 Whys began on the factory floor at Toyota, as a way to trace a mechanical defect back through each layer to its cause. It was adapted for human-centered design later.

Two things are true of a machine. A fault usually narrows down to a single cause, and a machine won't invent a reason it doesn't have when you keep interrogating it. Neither is true of a person. Human behavior has several overlapping causes, and people under pressure will manufacture a plausible-sounding one.

The drilling-down structure still works. But this is exactly why the answer you land on at the bottom can't be treated as the answer.

Don't Just Repeat "Why?"

This is the mistake almost everyone makes: firing "why?" five times in a row.

Two things go wrong. First, it feels like an interrogation, and the participant gets defensive. Second — and this is the serious one — people will generate a reasonable-sounding explanation on the spot rather than admit they don't know. Push someone for a reason they don't actually have access to, and they'll construct one. It'll sound thoughtful. It'll be fiction.

So keep the intent of the question and change the wording. Stay neutral, stay concrete:

"What was going on at that point?" "What led you to choose that?" "Could you give me a specific example from recently?" "Why did that matter to you?" "So if I've understood right, you were ______ — is that fair?"

Notice how many of these ask about what happened rather than what you were thinking. Memory of events is more reliable than memory of reasoning.

And know when to stop. If the answer has reached values, feelings, or life context — or if you've simply answered your research question — you're done digging. The participant's comfort and the natural flow of the conversation matter more than depth.

Which Questions Should You Use?

The shape of your question determines what you get back. There are five kinds worth knowing — three to build your interview from, and two to avoid entirely.

The three you'll use

1. Open questions are your backbone. They hand the floor to the participant and let them tell it their way.

"Tell me about the last time you used this service, starting from the beginning."

Build the interview around these. They're where the unexpected material comes from — the thing you didn't know to ask about.

2. Probing questions are how you follow. When an answer is vague, or when something interesting flickers past, a probe turns it concrete.

"What was the hardest part of that?" "Do you have a specific example?"

You can't script these in advance. They come from listening, which is exactly why listening beats preparing.

3. Closed questions confirm facts quickly — yes/no, how many, when.

"Did you use the app last week?"

Nothing wrong with these, as long as you don't stop there. A closed question should be a doorway: confirm the fact, then immediately open it up. "You did? Tell me about that time."

The two to avoid

1. Leading questions hide the answer you want inside the question.

"This feature was convenient, wasn't it?"

The participant now knows what you're hoping for. Most people are accommodating. You'll get agreement, and you'll learn nothing.

2. Rhetorical questions aren't really questions — they're the interviewer making a point.

"Who would enjoy a checkout process this complicated?"

You're not gathering data here; you're performing an opinion. And you've just told the participant what you think, which contaminates everything that follows.

The tell for both:

If you can predict the answer before you finish asking, don't ask it.

Start Wide, Then Narrow

Structure your questions like a funnel. Let the participant open up first, then zoom in on a specific moment, then check what it meant.

1. Open the experience

"Tell me about a recent time you used this service."

2. Zoom in on a moment

"Which step did you spend the longest on?"

3. Explore the decision

"What were you looking at when you decided that?"

4. Find the meaning

"Why did that matter to you?"

5. Check your understanding

"So the difficulty was really about ______ — have I got that right?"

That last step does more work than it looks like. Reflecting your understanding back gives the participant a chance to correct you — and people correct a wrong summary far more readily than they volunteer a missing detail.

Change the Question, Change the Answer

Look at the third pair closely. "Why did you do that?" sounds like a fair question, and it's the one this whole article is about — but phrased bluntly it can land as a challenge, and it asks people to narrate reasoning they may not have access to. "What influenced that choice?" asks the same thing while pointing at circumstances instead of at the person.

Key Takeaways

• Ask about recent, real experience. Don't build on hypothetical preferences or predictions about the future.
• The 5 Whys is a mindset, not a rule. The number doesn't matter; understanding does.
• Never repeat "why?" mechanically. It feels like interrogation, and it pushes people to invent plausible reasons.
• Open questions carry the interview; probing questions give it depth; closed questions confirm facts — then open back up.
• Leading and rhetorical questions inject your own view. If you can predict the answer, don't ask it.
• Reflect your understanding back so participants can correct you.
• One person's answer is a clue, not a conclusion. Verify against other participants, observation, and data.

In one sentence:

A good interview question doesn't extract an answer. It helps someone describe what actually happened to them.

Before You Go

A 10-minute exercise — run it on yourself

Think of something you decided recently. A subscription you cancelled, an app you deleted, a place you chose for dinner.

1. Write it down as a starting statement, then run a 5 Whys on yourself. Write each answer before you read your own next question.
2. Now go back and mark the exact point where your answers stopped feeling remembered and started feeling constructed. For most people that's somewhere around three or four.
3. Rewrite the question at that point as one about what happened rather than why you did it. Compare what you get.

That boundary you just found in yourself is the same one sitting in every participant you'll ever interview. Knowing where it is — and easing off before you cross it — is most of the skill.

What's Next

Affinity Diagrams: From Notes to Patterns

So far, it's all been gathering. Now you narrow — this is where Discover hands over to Define.

We'll cover:

• Building an affinity diagram from raw interview notes
• Organizing it against the assumptions you set out to test
• Pulling out insights that actually hold up

Remember the assumptions you wrote on your proto-persona? This is where you find out.

If this helped, stick around — follow the blog for the next one, and send it to a friend who's just starting out.

Thank you! 🙌