Concept
Leap-of-Faith Assumption
A leap-of-faith assumption is an untested belief that a plan depends on, the kind that would sink the whole venture if it turned out to be false.
Every plan for something new rests on beliefs that feel like facts until someone checks them. In The Lean Startup, Eric Ries calls the riskiest of these leap-of-faith assumptions. He sorts the big ones into two families. The value hypothesis asks whether people really get value from what you offer, enough to use it or pay for it. The growth hypothesis asks how new customers will find you once the first ones arrive. Most plans carry dozens of guesses, but they are not equally dangerous. The useful move is to find the one that is both critical and unproven. Test that one first, before you spend money building around it. That is where validated learning starts. You cannot learn anything about a guess you never wrote down, and an unnamed assumption quietly becomes the plan.
A real-life example
Dana wants to sell remote workers a monthly box of small-batch coffee for $28. Her value hypothesis is that they want a rotating local roast at home. Her growth hypothesis is that happy subscribers will gift boxes to colleagues. The first one is the real leap, because a supermarket bag costs $9. Instead of building a website, she posts a one-page preorder form in three remote-work forums. Forty people visit, and three pay. Now she knows what to fix.
How to use it
- 1Write your value hypothesis and your growth hypothesis as plain sentences that could turn out to be false, such as "Office managers will pay $50 a month for this."
- 2Circle the assumption that would sink the plan if it were wrong and that you have the least evidence for. That is your leap of faith.
- 3Design the cheapest test that could prove it wrong this week, and decide in advance which result would make you change course.