# How to run an assumption mapping workshop _Assumption mapping helps a team find the riskiest beliefs behind a plan. Learn the 60-minute agenda, the importance and evidence grid, and how to test what you find._ Assumption mapping is a short workshop where a team lists the beliefs its plan depends on. Then it sorts them by two questions: how important is this belief, and how much evidence do we have for it? Important beliefs with little evidence are the riskiest assumptions. The team tests those first. A focused session takes about 60 minutes. Every plan rests on beliefs. Customers have this problem. Team leads can buy without asking finance. The integration will take two weeks. Some of these beliefs are well supported, and some are hopes that have been repeated often enough to sound like facts. Assumption mapping helps the team tell the difference before it spends months building on the wrong one. If you want the facilitation handled for you, Clarvelo’s [Assumption Mapping workshop](/auth/register?user_return_to=%2Fapp%2Fworkshops%2Fassumption-mapping) runs the same 60-minute sequence. The AI facilitator collects the assumptions, guides the mapping and records which ones to test first. ## What is assumption mapping? An assumption is something that must be true for your plan to work, but that you have not proven yet. Assumption mapping makes these beliefs visible, then ranks them on a simple two-by-two grid. One axis shows importance: how much damage would it do if this belief is wrong? The other axis shows evidence: how much do we actually know today? The method is closely associated with David J. Bland, who describes it in the book *Testing Business Ideas*. Product teams, founders and researchers use it before they commit time or money. The result is a short, ranked list of assumptions to test, with a first test and an owner for each. ## When to use assumption mapping Use it when a plan is about to become expensive to change. Common moments include: - Before you build a new product, feature or service - Before a launch, a pricing change or a move into a new market - After a design sprint or discovery phase, when the team has a direction but little proof - When people disagree about what could go wrong and the discussion keeps going in circles It is less useful when the decision has already been made and nothing the team learns could change it. In that case, the session becomes a list of worries with nowhere to go. ## Who should join Invite up to eight people who see the plan from different sides. A typical group includes product, engineering and design, plus someone who talks to customers often, such as sales or support. Include the person who owns the plan and can decide what to test. Different views matter here, because each role tends to notice different assumptions. ## What to prepare - A one- or two-sentence description of the plan you want to examine - The decision this session should inform, such as whether to build, launch or invest further - Any evidence you already have: research notes, interview quotes, usage data or sales feedback - 60 minutes without other agenda items ## Assumption mapping agenda The agenda has two parts. First the group collects assumptions, then it maps and ranks them. Protect the second part. A long list without a ranking is not much help on Monday morning. - 25 minutes: collect assumptions about the business, the users and the risks - 35 minutes: map each assumption by importance and evidence, then choose what to test first ## Step 1: Collect assumptions (25 minutes) Read the plan aloud. Then ask one question: what must be true for this plan to work? Give people a few minutes to write on their own before anyone discusses. This gives quieter people room to think, and it stops the first idea from shaping all the others. Use three prompts to cover the ground: - **Business:** What do we believe about the customer need, the value we offer, how we reach customers, how we earn money and who we compete with? - **Users:** Who exactly are the users? When and where would they use this? What problem does it solve for them? - **Risk:** Which beliefs, if they turn out to be wrong, would cause the plan to fail? Write each assumption as a statement that could be false. “Pricing” is a topic. “Team leads will pay $20 a month without approval from finance” is an assumption you can test. Next to each one, note the evidence you have and where it came from. Then group duplicates so the map stays readable. > If you had to bet your own money that this is true, how confident would you be? What makes you unsure? > — A prompt for vague assumptions ## Step 2: Map importance and evidence (35 minutes) Draw a two-by-two grid. The vertical axis is importance, from low to high. The horizontal axis is evidence, from strong to weak. Then place each assumption by asking two questions: - If this assumption is wrong, how bad is it for the plan? - How much evidence do we have for it right now? Compare assumptions with each other when a placement is unclear. “Is this more or less important than the one we just placed?” is easier to answer than an abstract score. Keep importance separate from how vivid a worry feels. A dramatic scenario is not automatically an important one. ### Reading the four quadrants - **Important, little evidence:** These are your riskiest assumptions. Test them first. - **Important, strong evidence:** Build on these, and keep checking them as you learn more. - **Less important, little evidence:** Explore these later if a test is cheap. - **Less important, strong evidence:** These are safe to set aside for now. Use the last ten minutes to close. Read back the top-right corner in priority order. Ask whether anything important is missing or in the wrong place. Then choose one to three assumptions to test, and name an owner and a date for each. Park the rest clearly, so nobody leaves thinking every note is now a project. ## What to do with your riskiest assumptions An assumption map is only useful if it changes what the team does next. For each assumption you chose, write a short hypothesis that names who will do what and how you will know: > We believe team leads will start a trial without asking finance. We will know this is true when at least 30% of trial sign-ups come from team leads within four weeks. > — An example hypothesis Then pick the cheapest test that can give you a real signal. Good options include: - Five to eight customer interviews focused on one assumption - A landing page or sign-up button for a feature that does not exist yet, to measure interest - A manual version of the service, delivered by the team to a few customers - A clickable prototype tested with real users - A look at data you already have, such as support tickets or product analytics Agree on what result would change your mind before you run the test. Afterward, return to the map and move assumptions as evidence arrives. Over time, more of the important beliefs should move toward strong evidence. If the tests leave you with several options, a [feature prioritization workshop](/blog/how-to-run-a-feature-prioritisation-workshop) or a [Lightning Decision Jam](/blog/how-to-run-a-lightning-decision-jam-workshop) can help the team choose. ## Common assumption mapping mistakes - **Writing topics instead of statements.** “Onboarding” cannot be tested. “New users finish setup in one session” can. - **Mapping confidence instead of evidence.** Feeling sure is not evidence. Ask what you have seen, measured or heard from customers. - **Spending the whole hour collecting.** Ranking is the main output. Protect at least half the session for the map. - **Letting one voice place every note.** Ask for placements from several people, and discuss the ones where views differ. - **Trying to test everything.** Choose a small number of tests. The less important assumptions can wait. - **Ending without owners.** A map with no tests and no names is a nice picture of the team’s worries. ## How Clarvelo’s AI facilitator runs assumption mapping Clarvelo’s Assumption Mapping workshop is a 60-minute session for one to eight people. It has two phases: Assumption Collecting for 25 minutes and Assumption Map for 35 minutes. The output of the first phase becomes the input to the second. ### Assumption Collecting The AI facilitator starts by confirming the plan the group wants to examine. It asks what must be true for that plan to hold up, and it works through business assumptions, user assumptions and the biggest risks. For each assumption, it asks what evidence the team has and where uncertainty could change the next decision. When an answer is vague, it asks for something specific, such as which customer or which situation. At the end of the phase, it summarizes the list and checks that it is good enough to continue. ### Assumption Map The AI facilitator carries the collected list into the map. For each assumption, it asks how damaging it would be if the assumption were wrong and how much evidence the team has now. When the group is unsure, it helps them compare two assumptions directly. It suggests a zone for each assumption and asks the group to confirm or adjust it. Then it highlights the high-risk, low-evidence group, which it calls Investigate. This is the group to test first. To close, the AI facilitator reads back the priority order and asks whether anything is missing, ranked wrongly or dependent on another item. It separates the assumptions selected for action from the ones parked for later. It ends by naming owners and the next conversation, document or experiment the map should feed. ### Everyone can take part Guests join from a link and do not need an account. The person who organized the session can contribute as a participant instead of running the board. This matters in assumption mapping, because the organizer often owns the plan and holds many of its assumptions. The AI facilitator guides the process. The team still supplies the context, the evidence and the decisions about what to test. ## Frequently asked questions ### How long does an assumption mapping workshop take? Plan for about 60 minutes. Spend around 25 minutes collecting assumptions and 35 minutes mapping and choosing what to test. If you have less time, shorten the collecting step and keep the mapping, because the ranked list is the main output. ### What are the two axes of an assumption map? One axis is importance: how much damage it would do if the assumption is wrong. The other is evidence: how much you know about it today. Assumptions that are important and have little evidence are the riskiest, so you test them first. ### Who should take part in assumption mapping? Invite up to eight people who see the plan from different sides, such as product, engineering, design and someone who talks to customers. Include the person who owns the plan and can decide what to test. ### What should you do after an assumption mapping session? Turn each of your riskiest assumptions into a hypothesis with a clear success signal. Choose the cheapest test that gives real evidence, such as customer interviews or a prototype. Give each test an owner and a date, then update the map as results come in. ### How is assumption mapping different from a pre-mortem? A pre-mortem asks the team to imagine the project has failed and to explain why. Assumption mapping lists the beliefs behind the plan and ranks them by importance and evidence. The two work well together. Clarvelo runs both as AI-facilitated workshops. ### Do participants need a whiteboard account? Not with Clarvelo. Guests join from a link and contribute from their own devices. You do not need to set up Miro or Mural seats for each participant. ## Map the assumptions behind your next plan Clarvelo’s [Assumption Mapping workshop](/auth/register?user_return_to=%2Fapp%2Fworkshops%2Fassumption-mapping) guides up to eight people from a raw list of beliefs to a ranked map and a short list of tests. Guests join from a link, and the AI facilitator keeps time, carries the work between phases and records what the team chose to test. **Have a plan that depends on a few big beliefs?** [Sign up and start an Assumption Mapping session](/auth/register?user_return_to=%2Fapp%2Fworkshops%2Fassumption-mapping). Bring the plan and the people who know it. Clarvelo will run the workshop process. If your team is still exploring the problem, see [how to run a Day 1 Design Sprint workshop](/blog/how-to-run-a-day-one-design-sprint-workshop). Its output is a good starting point for an assumption map. --- Written by Joe Corcoran for [Clarvelo](https://clarvelo.com). Clarvelo is an AI facilitator that guides teams through retrospectives, decision making, problem solving, prioritization and 40+ workshop formats. [Read more on the Clarvelo blog](https://clarvelo.com/blog) or [try the live AI-facilitated workshops](https://clarvelo.com).