Decide
Assumption map
Also called Assumptions mapping
Place every assumption behind a plan by how important it is and how much evidence you have, to find what to test first.
- Time30 to 45 minutes
- People3 to 10 people
- Steps4
What it's for
Every plan rests on beliefs about customers, the market and what the team can build. The ones that are critical and unproven are where a plan fails. Mapping them shows which to test before spending more.
Write assumptions as statements that could be false: "Small teams will pay monthly" rather than "Pricing".
How to run it
List assumptions10 min
What must be true for this to work? One per note.
Place by importance8 min
How bad would it be if this were false? Move it up or down.
Place by evidence8 min
How much do we actually know? Move it left or right.
Plan the first tests10 min
For each note in the top-right quadrant, name a cheap way to test it.
Tips
- "Evidence" means something you saw, not something someone senior said.
- Desirability, viability and feasibility make good prompts for finding assumptions.
Where it comes from
Developed by David J. Bland and described in Testing Business Ideas (2019), which he wrote with Alexander Osterwalder.
Pairs well with
Hypothesis statement
Write an idea as a testable belief: what we'll build, for whom, the outcome we expect, and the signal that will show we were right.
Premortem
Imagine the project has failed, then work out why, so risks get named while there is still time to act on them.
Proto-persona
A quick persona built from what the team already believes, written down so the beliefs can be tested with research.