How Many Customers Should You Interview?

If you’re wondering how many customer interviews you should conduct, you’re not alone.

This is a really common question, and there are a few common answers.

First let’s discuss those common answers, and what they’re lacking, so you can understand the benefits of a different approach.

Not Useful Answer #1:

“Interview until you stop learning.”

Unfortunately, this approach isn’t very useful because, whenever you talk with anyone, you’ll be learning something new.

So the question ends up being, “When have you learned enough that you can move on to the next step?” which is just as difficult a question to answer as “How many people should I interview?” so you’re no better off than you were before.

Not Useful Answer #2:

“You should do X number of videos per week, or Y number of total interviews.”

I’m really not a fan of this approach.

If your goal is to interview until you have a certain number of conversations, you’ll end up focusing more on the quantity of interviews, and less on the quality – which will end up being a huge waste of time.

Let’s talk about a different approach, one that I find much more helpful.

The 3 of 5 Rule

Customer Interviews - 3 of 5 Rule

Here’s how I conduct interviews, and how I recommend you conduct yours:

  1. Start by interviewing a batch of 5 customers (one at a time)
  2. Analyze those interviews
  3. Repeat steps 1 and 2 until…
  4. At least 3 of the last 5 people you’ve interviewed, are Early Adopters.

By the way, if you haven’t read my articles on Early Adopters yet, you need to stop reading this, and read them now. Not only will they help you throughout your startup journey, it will be hard to make the most of the rest of this article without that context.

Early Adopters

Early Adopters - Seeking a Solution

You’ll recall from my previous posts, Early Adopters are customers who:

✓ Have the problem you’re trying to solve
✓ Know they have the problem you’re trying to solve
✓ Are actively seeking a solution to that problem

If 3 of the last 5 people you talk to are actively seeking a solution to the problem you’re trying to solve, you’ve found your Early Adopters.

Once you’ve found your Early Adopters, you’re ready to move on to your Offer Testing.

Why Batches of 5 Interviews?

Because interview quality is exponentially more important than interview quantity.

Interview quality > quantity

The whole point of doing these interviews is to do qualitative research.

This is your chance to do a deep dive with individual customers.

  • You can better understand what problems they’re seeking solutions for
  • Why they’re seeking those solutions and
  • Where they’re looking for solutions.

You’ll worry about doing quantitative research later on in Offer Testing, but for right now, you need to focus doing a small number of high-quality, in-depth interviews, with the right people.

If you try to interview more than five people at a time, you may accidentally force yourself to widen the scope of people you’re willing to talk to.

Interview Right People

Before you know it, you’re interviewing people across different customer segments, and ultimately you’ll be unable to find a pattern of the problems you’re trying to solve.

The other reason I recommend interviewing customers in batches of 5 is…

Patterns Emerge Very Quickly

Patterns emerge very quickly

When you’re interviewing Early Adopters you’ll quickly see…

Your Early Adopters will describe the same problems in the same way.

Once 60% (3 out of 5) of the people you’re talking to describe the same problems in the same way, you’ve found your Early Adopters!

Once you’ve confirmed you’ve found your Early Adopters on this small scale, you’ll be ready to do your Offer Testing, where you validate you can find your Early Adopters on a large scale – large enough to give you confidence you can achieve Product-Market Fit.

Keys to Efficient & Effective Interviews

Keys to Efficient & Effective Interviews

To get the best return on your interviewing investment, be sure to

1. Use Externally Observable Behaviors (EOBs) to interview potential Early Adopters

If you don’t know what EOBs are, or haven’t memorized the definition of Early Adopters yet, read this article and this one.

2. Use the 3 of 5 Rule:

a. Interview customers in batches of 5
b. Analyze the results. Niche. And Repeat if necessary.
c. You’re done interviewing when 3 of the last 5 people are Early Adopters

Want Some Help?

Now you know the fundamentals behind how many interviews you need to conduct, but it’s completely normal to still run into some trouble, like…

  • You’re interviewing customers but no pattern is emerging.
  • You’re having trouble even getting 5 interviews.
  • You’re not sure if you’re asking the right questions.

5-Interview Checkpoint

If any of the above applies to you, or you just want some more detailed guidance on customer interviewing, take a look at the 5-Interview Checkpoint. It’s the 11th exercise in the first FOCUS Framework workbook series and it will help you…

  • Analyze your interviews
  • Determine if you’ve met the 3 of 5 rule
  • Find a pattern amongst the problems
  • Figure out what to do if you aren’t getting interviews
  • Know what to ask during your interviews

The FOCUS Framework is used by thousands of founders to help them take action finding Product-Market Fit. Check it out and see if it can help you.

What’s Next

Now you know exactly how many customers to interview, and when you’re ready for Offer Testing.

Go out and talk to your customers!

1 comment
  1. Good reminder to link customer discovery interviews with not just learning customer pain, but also to identify who are early adopters, and what are their characteristics. I think myself and many others neglect to remember that not all customers are ready to buy a new product from an unproven startup. Its so important to find those people who are hungry for your product regardless of how risky it is.

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