Intuition
An issue tree is a family tree for a problem. You start with one big question at the top ("why are profits down?") and keep asking "what is this made of?" until each branch is small enough to actually measure. A messy problem feels infinite; a tree makes it finite — suddenly there are only six boxes to check, not a fog.
The profit tree is the single most reused tree in all of casework, because almost every business question eventually touches money.
Framework
- Start with the equation. Profit = Revenue − Costs. Revenue = Price × Quantity. Costs = Fixed + Variable. These identities are always true, so they're always MECE.
- Keep splitting until measurable. Quantity → existing customers × purchase frequency + new customers. Don't stop at "revenue is down" — push to which lever.
- Branch by one logic per level (the MECE rule from the last lesson).
- Then hypothesize. A tree isn't the answer; it's the menu. Pick the branch you suspect drives the problem and test it first.
Worked Example
A gym chain's profit drops 15%. You write the profit tree out loud: "Profit is revenue minus cost. Revenue is members × monthly fee. Costs are rent and staff (fixed) plus utilities and equipment (variable). Since rent rarely jumps overnight, my hypothesis is a revenue problem — specifically member churn. Can I see the membership trend?" In thirty seconds you've gone from a vague drop to a single number you want to see.
The tree earns its keep the moment it lets you say "I'd look here first, because…". That sentence is the whole point.
Pitfalls
- Drawing a beautiful tree and then never using it to pick a branch.
- Stopping one level too shallow ("it's a cost problem") instead of pushing to the driver.
- Reinventing the profit identity — Revenue − Costs is given, don't debate it.