Surface analysis: mapping the assumptions your plan is resting on

A plan is a surface. It looks solid from above, and it is held up from below by a small number of assumptions that rarely appear in the deck.

Surface analysis is the practice of finding those assumptions and measuring how much weight each one carries.

Step one: list the dependencies, not the goals

Goals describe where the plan is going. Dependencies describe what has to remain true for it to get there. Ask the team: if this plan fails in a year, what will we say we got wrong? Write down every answer. Those are your dependencies.

Step two: sort by load

For each dependency, ask what happens to the plan if it turns out to be false. If the plan adjusts, the dependency is light. If the plan stops, the dependency is load-bearing. In our experience most plans have three or four load-bearing assumptions, and at least one of them has never been discussed.

Step three: test the heaviest first

You will be tempted to test the assumptions that are easiest to check. Resist this. Test the one carrying the most weight, even if it is the hardest, because it is the one most likely to end the plan.

A diagram we use

We draw the plan as a horizontal line and each assumption as a vertical post beneath it, with height proportional to load. Teams find this clarifying. It also occasionally reveals a post that is holding the plan up from above, which we have not yet found a satisfying way to diagram, and which we flag for further study.