This is a list of triggers to help you get started. Once you start identifying assumptions, it will become clearer what other beliefs you hold about how you plan to build, design, distribute, and create value with your product. You may think that there’s no way you’re going to be right about your cost structure or key partners on day one, and that’s probably right. Steve Blank likes to quote boxer Mike Tyson on prefight strategies.
“Everybody has a plan until they get punched in the mouth.” It’s not important that you’re right; it is important that you write down your assumptions. They serve as a critical reminder to you that you haven’t yet proven or disproven them. After you’ve finished, if you’ve done this as a group, spend another 10 minutes clustering similar sticky notes. For example, put all the sticky notes around “Customers have X problem” together. You’re likely to see assumptions that contradict each other, even within a small group. Finding these internal misalignments will help your product even before you start talking to customers!
You will want to refer back to your assumptions throughout your customer development process—at first as a reference for finding customers and thinking of questions to ask, and later to annotate them as you collect evidence that validates or invalidates them. Now that you’ve completed a brain dump of your assumptions, it’s time to come up with a simple, provable hypothesis.