Assumptions and Experiments
Every concept rests on beliefs nobody has tested. This lesson covers surfacing those assumptions, working out which of them would sink the idea if they turned out to be wrong, and designing the smallest experiment that would tell you.
After this lesson you can
- Surface the beliefs a concept is quietly resting on.
- Sort them by consequence rather than by how cheap they are to test.
- Design the smallest experiment that would actually change your mind.
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Module Overview
Once an idea is a prototype and real people have seen it, the next move is to get at the assumptions hiding inside it, particularly the ones about people changing their behaviour. Every new idea is stuffed with them. The method is two steps: list what you are assuming users will value or be willing to do, then design small, low-risk experiments that test one of those at a time.
Uber is the worked example, imagined back at the start. The assumptions include that people will drop the cab firm they already use, that they will get into a stranger's car, and that they will let a company track where they are. One cheap test of the first: hand out cards for a lesser-known local cab company with ten per cent off, and count how many are redeemed. Small spend, real learning, and worth clearing with the cab firm first.
Run many short experiments rather than one big one, and start with the assumptions that carry the most risk. Watch for behaviour you were not testing for, because the most useful thing you learn is often an accident. Agree a time and money limit per experiment as a team, keeping them fast and cheap early and allowing more room as the idea firms up.
Where this usually goes wrong
- Testing whichever assumption you happen to be able to test this week.
- Running a survey about money, which asks for an opinion where you need a commitment.
- Deciding in advance what the experiment will show, so no result can count as a no.
Check it landed
3 questions, and one of them has no right answer. You get the reasoning either way.
You have surfaced eleven assumptions behind your concept. Which do you test first?
"We will find out once we have built it." What is the flaw?
Your riskiest assumption is that people will pay twenty pounds a month. What is the smallest experiment worth running?
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Put it to work
3 templates go with this lesson. Each one has its own guide on when and how to use it.
