Assumption mapping
Assumption mapping is a tool that helps you check whether what you think you know about your product, service and users is actually true.
By mapping and challenging your assumptions early on in a project, you can avoid going too far down the wrong road based on false or biased assumptions. This will save you time, effort and money.
An assumption map will help you to figure out which of your assumptions are the riskiest. Then you can prioritise testing them to see if they are true.
Assumption mapping is best done as a group with your stakeholders. You can do it in person using pens and sticky notes, or online using a virtual whiteboard like Mural or Miro.
See our guidelines on running accessible sessions in the introduction for tips on making sure nobody is excluded.
Assumption mapping can be as short as 10 to 30 minutes. But you can spend longer if you need to.
Assumption mapping can take many forms depending on why you’re using it. But there are 3 main stages that any process will follow:
- Define
- Map
- Test
Defining
First, choose a suitable framework that will guide your process. 2 common frameworks involve mapping assumptions about:
- the present – an existing system, service or user journey
- the future – what is viable, desirable, ethical and usable for a future system, service or journey
Defining the present
To assumption map an existing system, service or journey:
- Create a table with rows labelled Doing and Feeling, like this:
- As a group, add a label for each step at the top of each column. Add as many columns as you need to
- Ask people to write what they assume the user is doing at each stage
- Then ask them to write what they assume the user is feeling at each stage
- If you want, you can add more rows for things like thinking and saying
- As you are doing this, discuss as a group why people are making those assumptions
Defining the future
To assumption map ideas you have for a future system, service or journey:
- Create 3 lists headed feasible, viable and desirable. This could be in a table, on a whiteboard, or just on a piece of paper
- Under each heading discuss and write down assumptions about an idea
- Feasible means whether you can do something (with the resources you have). Is it possible?
- Viable means whether it’s worth you doing something (or if it’s too difficult or expensive)
- Desirable means whether you and your users actually want an idea or not
- A helpful way to do this is to think about what has to be true for an idea to be placed under each heading. For example, ‘for this idea to be viable we will have to build it in 3 months’
- Repeat this for each idea you want to think about
- If you want, you can consider more headings, like ethical and usable
Mapping
Draw a 2-by-2 matrix, like this:
- Label the axes with whatever is useful to help you decide which of your assumptions is the riskiest
For example, less confident/more confident vs more impact/less impact - If you have low confidence in a high-impact idea, that is a good candidate for testing
Testing
Now you need to test your riskiest assumptions. For example, assumptions about:
- market trends could be checked using desk research
- desirability could be tested using research interviews
- user behaviour could investigated using card sorting