What is a tree diagram?
A tree diagram bridges the gap between a goal and the work needed to reach it. Goals such as "halve damage complaints" are too broad to act on; a tree breaks them into the main strategies, then sub-strategies, then specific actions. Because each level answers "how?" for the level before, and each level is also the "why?" of the level after it, the tree shows that every action contributes to the goal and that nothing important has been left out.
How to build a tree diagram
- Write the goal in a box on the left: specific and measurable.
- Brainstorm the first level: the main ways to achieve it. Aim for 3 to 5.
- Repeat "how?" for each box until the branches end in concrete actions.
- Check right to left: if we do all the boxes under one, will that box be achieved?
- Assign owners and dates to the actions and move them into a plan.
Tree diagram example
The goal is to halve customer complaints about damaged deliveries by June. Three ways are identified: protect products better in the box, handle fragile items with care in the warehouse, and improve carrier performance. Each is broken down into actions such as testing three carton designs, drop testing to ISTA 3A, training pickers, marking fragile cartons and adding a damage clause to carrier contracts, each with an owner and a due date.
Other uses of the tree diagram
- CTQ tree: break a customer need into measurable requirements.
- Work breakdown: split a project into deliverables and tasks before scheduling them on a Gantt chart.
- Contingency planning: add "what could go wrong" to the actions with a PDPC.
- Choosing between means: score the options with a decision matrix or impact/effort matrix.
How to use this Tree Diagram tool
- State the goal. Click the dark box and write the goal, as specifically as you can.
- Ask "how?". Click + next to the goal to add the main ways to achieve it (first level).
- Go deeper. For each box, click + and ask "how?" again until each branch ends in a concrete action.
- Check the logic. Read each branch backwards: would doing this achieve the box before it? Fill any gaps.
- Assign the actions. Click each action (the green leaves) to give it an owner and a due date.
- Export. Export the tree to PDF or PNG, and the action list to Excel.
Frequently asked questions
What is a tree diagram?
A tree diagram (also called a systematic diagram or how-how diagram) breaks a broad goal into progressively more detailed levels. Each level answers "how?" for the level before it, until the branches end in concrete actions that someone can own. It is one of the seven management and planning tools.
How do you make a tree diagram?
Write the goal on the left. Ask "how could we achieve this?" and add the answers as the first level. For each, ask "how?" again. Stop when each branch ends in a specific action. Then check each branch in reverse: "if we do this, will it achieve the level above?" (the why-why check).
How many levels should a tree diagram have?
Usually three to four levels below the goal. Stop when the actions are specific enough to assign and schedule; going further adds detail without adding clarity.
What is the difference between a tree diagram and a fishbone diagram?
A fishbone diagram works backwards from a problem to its possible causes. A tree diagram works forward from a goal to the means and actions needed to reach it. The tree is a planning tool; the fishbone is an analysis tool.
What is a CTQ tree?
A critical-to-quality (CTQ) tree is a tree diagram used in Six Sigma that breaks a customer need into drivers and measurable requirements. The structure is the same; only the questions differ ("what does the customer need?" instead of "how?").
What comes after the tree diagram?
Turn the actions into a plan: assign owners and dates, then track them in an action plan or Gantt chart. For risky plans, add a process decision program chart to prepare for what could go wrong.