Accessibility considerations

How to keep a tree readable for everyone, including people who cannot rely on color.

Why it matters

The standard notation tells node types apart by color. Color is fast, but it is not available to everyone:

• Color vision deficiency affects roughly 1 in 12 men and 1 in 200 women. The most common forms confuse reds, browns, greens, and oranges, which are exactly the colors of roots, branches, and leaves.
• Grayscale printing turns every color into a shade of gray.
• Projectors, screens, and tools shift colors, sometimes enough to make two types look alike.

Here is the same small tree, in grayscale, without and with text markers:

A tree that relies on color alone excludes some readers. The options below make it readable for everyone.

Text markers

The simplest option: add a short marker to each node, next to its text.

• Put the marker at the start of the node's text, at the end, or in a corner, whatever your tool makes easy. Stay consistent within a tree.
• Markers supplement color. They do not replace it.
• List the markers in the legend, next to each color: "■ [P] Root / Problem."
• Markers are cheap to add during a live session, so they work even when construction speed matters.

Every Tree of Influence on this website uses text markers, except the comparison above.

Shape variants

Tools with several node shapes, such as Miro, Mural, and Lucidchart, let you give each type its own shape instead of, or in addition to, markers. There is no prescribed mapping. Any consistent one works, as long as the legend documents it. For example:

Shapes are slower to work with than markers, because people have to pick a shape for every node. Use markers during live sessions, and consider shapes when a tree is being drawn deliberately, for example when cleaning it up to share.

Using shapes replaces the "one shape for every node" default. Say so in the legend.

Text contrast

Node text must be easy to read against its color:

• Dark text on amber nodes. White text on amber fails common contrast standards.
• White text on dark brown, forest green, and indigo nodes.
• On a physical wall, write in large block letters with a thick marker. Thin pens and small handwriting are hard to read from a few steps away.

See colors and shapes for the standard colors and text colors.

Sharing a tree

Board tools are mostly invisible to screen readers. When you share a tree with people who were not in the room, consider adding a text version: a list of the nodes by type, and a list of the arrows ("Documentation is out of date" influences "New hires ship something in their first month"). Every diagram on this website has one, under "Diagram as text."

How the accessibility layer works

• It is optional. Add it when your participants or readers need it. A tree without markers is still a valid tree.
• It does not change the standard. Colors, arrows, and orientation stay the same for everyone. The layer only adds information.
• It goes in the legend. If a tree uses markers or shapes, its legend says so.

Still being explored

Text markers and shapes address color vision. Other needs, such as cognitive load during large sessions or participation in physical sessions, have not been studied yet. If you have adapted the Tree of Influence for an accessibility need, share what you learned.