Published in


3 Steps To The Perfect Design Sprint Question

1. Critical Assumptions 2. Testable Hypothesis 3. Sprint Question

Last month, my colleague Leon Voon and I completed our first Design Sprint (inspired by Jake Knapp’s book) in Hong Kong — condensed into three days instead of the usual five. In retrospect, it was more of a “Dash” than a “Sprint”.

The Design Sprint process is “a five-day process for answering critical business questions through design, prototyping, and testing ideas with customers,” basically, an ingenious way of combining Design Thinking, Lean and Agile methodologies into a new way of working.

Yet, I believe there were some parts that could have been fleshed out more thoroughly in the book. In particular, the relationship between critical assumptions, hypotheses and sprint questions, proved to be especially confusing for us.

During one of our discussions, I realized that we could tackle this challenging portion by breaking down the whole process. So, here is my take on a mental model that helps to map out these relationships:

How would this model play out in a real life scenario? Introducing… the Cavity Zapper!

Imagine that you are trying to create a product “The Cavity Zapper” that would help you brush your teeth. You have decided to build and test some features of The Cavity Zapper through a Design Sprint.

Critical assumptions for this product would most likely include things like “The toothbrush authorities will approve this product” or “This product can clean teeth more effectively than a manual toothbrush”.

“The toothbrush authorities will approve this product” can be filed away as an Untestable Assumption — whether the toothbrush authorities decide to approve The Cavity Zapper would most likely not be under your control. On the other hand, the assumption “This product can clean teeth more effectively than a manual toothbrush” can be easily turned into a testable hypothesis such as “The Cavity Zapper takes half the time to clean a person’s teeth than a normal toothbrush does”. The key to a testable hypothesis is to create one that is measurable and comparable — whether qualitatively or quantitatively.

At this point, you may have multiple testable hypotheses. You now have to decide which one(s) you want to focus on for the sprint. The crucial one(s) should be chosen for your sprint and the rest reserved for future sprints. Now, you can turn your chosen testable hypothesis into your official sprint question! In the case of The Cavity Zapper, the testable hypothesis “The Cavity Zapper takes half the time to clean a person’s teeth than a normal toothbrush does” can be turned into a Sprint Question such as “Will customers want to switch to a product that cleans their teeth in half the time?”.

What do you think? I would love to hear your feedback and thoughts!

Interested in partnering with the LOFT? We’d like to hear from you! Get in touch with us via You can also follow our innovation journey on Instagram,LinkedIn, Periscope, Facebook and Twitter!



The LOFT: Lab of Forward Thinking™, is a platform that explores emerging technologies, new business processes and consumer needs to deliver innovative solutions. This is an ecosystem with centers in Boston, Singapore & Toronto.

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store