“If it disagrees with experiment, it’s wrong.” - Dr. Richard Feynman

In every project, there are assumptions being made by the team regarding important considerations such as:

  • Who is/are our user(s)?
  • What is the best way to provide value to our customers?
  • Who are our customers?
  • Who are our competitors?
  • What is/are the most important problem(s) to solve?

And many more. By identifying these assumptions early in the process, we can determine ways to test the assumption and get data that will help mitigate the risk of being wrong.

There are many exercises that can help do this. This exercise was created by Giff Constable and found in the Lean UX book by Jeff Gothelf and Josh Seiden. It provides a quick way for a team to determine their individual assumptions and then share them see how they differ within the team.

Why use this exercise?

Often times, something that seems obvious to a team member changes when they see that there are multiple perspectives in the group. Having the team outline their assumptions individually allows each team member to be heard by reducing the possibility of group thinking. Also, by providing a guideline of areas to focus assumptions on, it makes it easy to see how team views differ.

Note: The worksheet is simply meant as a guideline. Teams can and should edit it to fit the needs of their project. Instructions should also be given to the group to feel free to add any additional assumptions they have that might not fit into the categories on the worksheet.

Our approach

  • Step 1: Complete the assumptions exercise individually. Each member of your team should prepare answers for the questions that follow on their own. This includes your clients.
  • Step 2: Share your answers. Get together with your team (and client) to kick off the new initiative. Go around the table sharing everyone’s answers to the assumptions exercise, question by question.
  • Step 3: Collect, organize, prioritize. Collect these answers on sticky notes or a whiteboard and sort them into themes. As a team, attempt to prioritize which themes are most important for each question. Don’t worry if you get to the end of the exercise without clear agreement on all of the answers. The goal is to collect statements that reflect what you and your team think might be true. If you have strong disagreement on a point, capture the different perspectives.

Alternate Approach

The primary benefits and insights gained from this exercise come from discussions about differing point-of-views, so gathering the team together to perform it is ideal. However, if your team is large and/or it is impossible to schedule a meeting where everyone can attend, this form can also be distributed via Google Forms or some other survey tool.

If using this method, make sure to have a place where everyone can view the results. We use Google Forms because all team members can access results through Google Drive. You will also need some sort of team communication tool where people can share their thoughts. Our team uses Slack because, well, it’s awesome for this sort of thing.

Through your team discussion, make sure you are addressing Step 3 from above.

How long does this take?

If done as a group, approx. 45 minutes to 1 hour.

If done as survey, you should give the team a couple days to find time to complete and provide a clear deadline for submission. Be careful not to give too much time since it will likely get overshadowed by other work and forgotten. After deadline, send notice to team that it is ready for review with a link to where they can find the responses. Give them a new deadline to provide any thoughts about what they read. Again, no more than a couple days.


Quick (if done as a group) and effective (if done either as a group or through survey) way to identify risk and prioritize mitigation efforts.


  • Lean UX - also available at Safari Books Online