Pie & donut encodes values as angle (and area) of a circle slice. Playfair 1801; Florence Nightingale’s coxcomb is a polar cousin, 1858.
In reports, ads and assignments it fits two to five parts that sum to a meaningful whole. Skip it when many similar slices, 3-D pie, or comparing two pies.
Mistakes
- Failure modes 1 — many similar slices, 3-D pie, or comparing two pies
- Failure modes 2 — 3-D pies and perspective bars
- Failure modes 3 — Dual axes that fake a correlation
- Failure modes 4 — Truncated axes that shout a small delta
- Failure modes 5 — Legend only, no direct labels
- Failure modes 6 — Missing source, unit or period
Fixes
- Fixes 1 — Return to two to five parts that sum to a meaningful whole.
- Fixes 2 — Flat, one axis, direct labels.
- Fixes 3 — Color-blind-safe palette plus pattern.
- Fixes 4 — Rewrite the title as a claim and add a source line.
Pie & donut: honour angle (and area) of a circle slice, and switch when many similar slices, 3-D pie, or comparing two pies.