Assumption Mapping Template

The grid has two axes: importance to success on the vertical axis, and level of evidence on the horizontal axis, running from pure guess to strongly supported. Assumptions get written on individual cards and grouped into three categories: desirability, whether users actually want this; feasibility, whether the team has the skills and technology to build it; and viability, whether it makes business sense. A fourth category, ethical risk, covers assumptions about unintended harm the other three can miss.

Plot each assumption where it belongs on the grid, and the top right quadrant, high importance paired with low evidence, becomes the leap of faith zone: the assumptions that could kill the idea and that nobody has actually checked yet. An example: a team building a B2B expense tool assumes finance managers will trust an AI generated approval recommendation enough to act on it without double checking every line. That assumption is high importance, since the whole feature depends on trust, and low evidence, since nobody has watched a finance manager use it yet, so it lands squarely in the leap of faith zone and becomes the first thing to test.

Use this template right after a lean canvas or an opportunity solution tree, once a team has a solution direction in mind but before committing engineering time to build it. It works best as a live group exercise: each person writes assumptions independently on cards first, then the group places and debates them together, which surfaces disagreement about what is actually known versus assumed.

Fill it in by writing one assumption per card in plain language, specific enough that a test could prove it false, not a restated feature description. Color code by category, desirability, feasibility, viability, and ethical, so the grid shows at a glance whether a team is over indexed on one type of risk while ignoring the others. Then convert every card in the leap of faith zone into an experiment backlog: a specific, small test with a stated pass or fail threshold.

The most common mistake is writing assumptions that are actually facts already known from prior research, which clutters the low evidence axis and hides the ones that genuinely need testing. A second common mistake is stopping at the mapping step and never converting the leap of faith assumptions into real experiments, so the exercise produces a nice looking board and no change in what gets tested next.

Builders Camp's Discovery Expert Track pairs this template with the opportunity solution tree template for sizing which solution branch to test first. Both templates live in the Builders Camp templates library, included in every Membership alongside 47 other templates and the tracks and bootcamps that teach how to use them.