# Assumption Mapping

> Teams list the assumptions behind a plan and map them by importance and evidence, to see which ones need testing first. Duration: 45 minutes. Group size: 4–30 people. Setting: Hybrid. Below you will find a step-by-step guide, the materials and facilitator tips.

URL: https://bravodays.com/en/team-building-library/assumption-mapping
Last updated: 2026-10-21
Publisher: BravoDays (https://bravodays.com)

## Key facts

- **Duration:** 45 minutes
- **Group size:** 4–30 people
- **Setting:** Hybrid
- **Energy level:** Calm
- **Materials:** A wall or board with a two-by-two grid: important / less important, little evidence / strong evidence, Sticky notes in two colours, Markers
- **Price:** Free, no sign-up

## Objective

Make hidden assumptions visible and decide which ones to test before committing more time or money.

## Materials

- A wall or board with a two-by-two grid: important / less important, little evidence / strong evidence
- Sticky notes in two colours
- Markers

## Step by step

1. Describe the plan or project in two sentences at the top of the board.
2. Each person silently writes assumptions the plan depends on, one per note: about customers, money, people, timing and technology.
3. Read the notes aloud, remove duplicates and rewrite vague ones as statements that could be true or false.
4. Place each note on the grid: how important is it for the plan, and how much evidence do we have?
5. Focus on the "important, little evidence" corner and choose the top three assumptions.
6. For each of the three, agree a quick, cheap way to test it, an owner and a date.

## Facilitator tips

- Push for specific statements: "customers will pay 20 percent more for faster delivery" is testable; "customers like speed" is not.
- Ask "how do we know?" whenever a note is placed in the strong-evidence column.

## Related pages

- [Team building library](https://bravodays.com/en/team-building-library)
- [Get a quote](https://bravodays.com/en/get-a-quote)