Chapter 2: Find out if you're wrong, before you build, lesson 7 of 7

Make your assumption map

The project for chapter 2. Take a real idea and list the beliefs it rests on. Rank them by risk, then turn three into tests you could run, each with a date.

By Shirish Shikhrakar1 min read, 30 min of exercises

This is the real work of the chapter. You make an assumption map for one idea, and turn its riskiest beliefs into tests. It uses everything from the last five lessons.

Use an idea from your own work if you can. It could be a feature someone asked for, or one you want. If you don’t have one, take this request. Nora Kim is Tiffin’s growth manager.

Nora, growth manager, to the product team: Let’s give a free lunch to anyone who orders 10 times in a month. People will order more to get it.

Each step shows an example from my own idea for teachers. Take your time. You can leave and come back, and it will still be here. If you get stuck on a part, open the help under it.

Make your map, one step at a time

Your project

One page for a real idea or feature request. The beliefs it rests on, ranked by risk, and three of them turned into tests you could run. It saves in this browser as you type. Nothing is sent anywhere.

Step 1 of 4 The idea

Which idea? Pick a feature request or idea from your own work, or take Nora's. Example: Show teachers how each student's code was made, day by day.

Stuck? Get help with this part

Think about this: What has someone asked your team to build lately?

What has to be true for it to work? Write at least four beliefs, each starting "We believe that". Example: We believe that teachers will open the code history. We believe that students can't fake a history easily. We believe that teachers grade by the work, not by who wrote it.

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Think about this: Who has to do something new for this to work? Why would they?

Step 2 of 4 Rank them

How much proof do you have for each belief? Name its rung on the ladder, from 0 to 6. Example: Teachers will open it: rung 0, my guess. Faking is hard: rung 0. Teachers grade by the work: rung 1, one teacher's story.

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Think about this: For each belief, ask: did anyone see this happen, or count it?

If each belief is false, which other beliefs stop mattering? Example: If teachers never look at the history, faking it does not matter.

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Think about this: Picture one belief turning out false. Which others would you stop caring about?

Which belief do you test first? Use all three questions to say why. Example: Teachers will open the history. The idea dies without it, I have no proof, and the faking question rests on it.

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Think about this: Which belief sits lowest in your stack, with the least proof?

Step 3 of 4 Three tests

Turn your first belief into a test. What do you change, for whom, and what will they do? Why? What result means you're wrong, and when do you decide? Example: We show one teacher the code history on ten pretend assignments. He'll open it to grade, because it shows understanding. We're wrong if he uses it for fewer than 8. We decide on 16 October.

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Think about this: Answer Mia's six questions from lesson 2.2, one at a time.

Now your second belief, the same way. Example: We ask three students to fake a week of history for code an AI wrote. We're wrong if any fake fools the teacher. We decide on 23 October.

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Think about this: Which result would you hate to see? Make that the one that means you're wrong.

And your third belief. Example: We show a teacher the same pretend work twice, once with names and once without. We're wrong if his grades don't change. We decide on 30 October.

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Think about this: Give the number a reason. Why that number, and not one a bit higher?

Step 4 of 4 The first test

What will you do this week to run test 1? Who has to agree to it? Example: Ask a teacher I know to grade ten pretend assignments, with names hidden. He agrees first, and no real grades are used.

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Think about this: Which of the five tests from lesson 2.5 fits in a day?

Which rung can this test reach? What decision can that carry, and what can't it? Example: Rung 3, one teacher watched. Enough to build a rough history view for him. Not enough to build it for every school.

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Think about this: Is the next step cheap and easy to undo? If not, what proof would it need?

Which beliefs are you still unsure how to test? Write each one as a question. Example: Would students work differently once they know the history is shown?

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Think about this: Read your map again. Which belief has no test yet?

Your assumption map

The idea
The beliefs
The proof
What rests on what
Test first
Test 1
Test 2
Test 3
This week
What it can decide
What I still need to find out

Before you copy it, check it. Tick each one that is true. Each belief is one belief, and starts with "We believe that". You named a rung of proof for each belief. You test first the lowest belief with no proof, not the easiest one. Each test has a number that means stop, a reason for it, and a real date. Your first test says who has to agree to it. At least one test could give a result you'd hate to see.

Written by

Shirish Shikhrakar

Shirish is a Google-certified UX designer and UX engineer based in Kathmandu, Nepal. He started as a software developer, moved into product design for Silicon Valley startups, and has taught UX foundations to hundreds of designers since 2019.