Stop 03 · User Research & DiscoveryTopics · 10/12

Assumption Mapping

In short

Every product idea rests on a pile of guesses. Assumption mapping finds the one guess that would sink you if it's wrong, so you test that first.

Listing every assumption a product idea depends on and ranking them by risk and uncertainty — so you test the riskiest, least-known assumptions first.

The purple blob with a backpack carefully tests a rope bridge with a stick.

Think of it like this

The monsoon trek

You assume the bus runs, the trail is open, the rope bridge holds and it won't pour. If the bus is late, you wait. If the bridge breaks, the trek is over. So you check the bridge before anything else.

Watch it happen

Three kinds of risky guesses

Notes-sharing app

Desirable?

Viable?

Feasible?

Toppers will share

Students pay Rs 49

Scan quality is OK

1/5Start with the idea. Write every assumption it needs to be true, one per sticky note.

The big ideas

What you need to know

Write them all down

List every assumption, even obvious ones. Unspoken assumptions are the ones that surprise you later.

Importance vs evidence

Plot each on a 2x2. High importance and little evidence goes to the top of your test list.

Test the riskiest first

Design a small, cheap test for the scariest assumption before writing any code.

Save yourself the pain

Common mistakes

Oops

Testing the easy assumptions because they're comfortable.

Do this instead

Test the one that would kill the idea if it's wrong, even if the answer might hurt.

Oops

Doing assumption mapping once at the start and never again.

Do this instead

Revisit it as you learn. New evidence moves assumptions around the map.

Your mission

Map and test one assumption

~35 min

Quick check

Which assumption should you test first?

Go deeper

1List every assumption behind a feature idea, big and small.
2Rank them on a 2x2 of importance vs certainty.
3Design the cheapest possible test for your riskiest assumption.