Funnel encodes values as width (or area) of successive stages. Sales-management language of the mid-20th century; later CRM dashboards.
In reports, ads and assignments it fits ordered drop-off: leads, checkouts, applications. Skip it when stages are not nested subsets of the same population.
Parts
- Mark — The core mark of Funnel is width (or area) of successive stages.
- Scale — The scale must show zero (or a declared break) and units.
- Axis — Axis titles name the variable, not a mood.
- Legend — A legend is weaker than a direct label. Write beside the mark when you can.
- Label — Numbers are optional. If comparison is the job, label the ends only.
- Grid — Keep the grid faint. Data should own the ink.
- Annotation — One annotation sentence. Date the source.
- Frame — A thin frame. Never a 3-D box.
Variants
- Conversion funnel — Variant 1 of Funnel. Same encoding, different layout.
- Sales pipe — Variant 2 of Funnel. Same encoding, different layout.
- Drop-off chart — Variant 3 of Funnel. Same encoding, different layout.
- Funnel 4 — Variant 4 of Funnel. Same encoding, different layout.
Labels
- Axis — On Funnel, make Mark readable.
- Legend — On Funnel, make Scale readable.
- Label — On Funnel, make Axis readable.
- Grid — On Funnel, make Legend readable.
- Annotation — On Funnel, make Label readable.
Funnel: honour width (or area) of successive stages, and switch when stages are not nested subsets of the same population.