The Unknown Unknowns

Apr 19, 2021

by Charlotte Oxnam, McCormick ’23

In the MIT Sloan Management Review case study Discovering “Unk-Unks”, author John W. Mullins argues that the most useful insights for a founder are the “unk unks,” the unknown unknowns. These are the answers to questions you didn’t know that you needed to ask but provide extremely valuable insight to your product and company. While surveys and interviews are great while doing customer research, they are limited by the questions being asked. The long interview method solves that issue.

What is a long interview?

A long interview is an interview where very few questions are actually asked but, instead, the interviewee is encouraged to talk more about whatever they are thinking. The basic format is as follows:

  1. Quick biographical questions. Where the interviewee is from, their background, etc.
  2. A couple of open-ended questions. These should be purposefully vague - for example, “How do you go about dealing with X problem now?”
  3. Dig deeper follow ups. When the interviewee finishes answering the question, find something to ask that allows them to dig deeper. You can do this by raising an eyebrow at a certain statement, asking them to elaborate, even just repeating a word that they say as a question.
  4. Situation changers. Ask “what if Y wasn’t available? What about Z? Why don’t you use that?”

There are many mistakes that are easy to make during a long interview. Try to refrain from leading questions and questions with short yes or no answers. Avoid cutting off the interviewee, and try to curb your enthusiasm for your product. No one likes to hurt someone’s feelings and if you seem too enthusiastic about your specific solution, you are much less likely to get true and honest feedback.

This approach to customer research can help you uncover powerful insights early on that will allow your product or service to reach a much better market fit from the beginning. It helps you get out of the seller mindset and into the mindset of your ideal customer. This can prove invaluable for your startup.

This article was written by Charlotte Oxnam. Charlotte is an industrial engineering student at Northwestern and the founder of, as well as a student aide at The Garage.

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