The legend
What every legend must contain.
Every Tree of Influence must have a legend.
A legend takes seconds to create and saves every future reader from guessing, including the people who built the tree, two months later. A tree with a legend can be read by a stranger. A tree without one needs someone in the room to explain it.
What a legend contains
- Node types in use: one entry per color, with a swatch and the type name.
- Arrow styles in use: one entry per line style, with its meaning. Leave this out if the tree uses only the default solid arrow.
- Flow: which way the tree grows, for example "roots (bottom) → outcomes (top)."
- Text markers, if the tree uses them.
- Context: what the tree is about, who built it, and when.
Leave out anything the tree does not use. A tree with no artifacts has 3 node entries, not 4.
A complete example
This tree uses every node type and every arrow style, so its legend lists them all.
Diagram as text: A tree that uses every node type and arrow style
Nodes:
- Root / Problem: "Documentation is out of date"
- Root / Problem: "Setting up a laptop takes a week"
- Action / Intervention: "Write a one-page starter guide"
- Desired State / Outcome: "New hires ship something in their first month"
- Artifact / Deliverable: "One-page starter guide"
Arrows:
- "Documentation is out of date" influences "Write a one-page starter guide"
- "Write a one-page starter guide" influences "One-page starter guide"
- "One-page starter guide" influences "New hires ship something in their first month"
- "One-page starter guide" attacks "Documentation is out of date"
- "Setting up a laptop takes a week" blocks "New hires ship something in their first month"
The legend of the finished tree in the Quick Start also shows votes and context.
Where to put it
- Put the legend in its own area, outside the space the nodes occupy.
- Make it visible in any view that shows the whole tree, without scrolling.
- On a digital board, create the legend first, before any nodes. It tells participants that the legend is part of the work, not an afterthought. If you use a starter board, that is included.
Keep it current
Update the legend every time the tree's meaning changes: a new color, a new arrow style, a new marker. The legend is the contract between the diagram and every future reader.