Baseline: what the figure rules are compared against

This file names the figure a proposed figure design must beat, and how the two would be compared.

The baseline named

  • Practice baseline: the Urban Institute data visualization style guide (Urban 2025, updated 2025-08-27).
  • Testable floor: WCAG 2.2 success criteria 1.1.1 and 1.4.11 (W3C 2023e, W3C 2023g, W3C 2023a).
  • Peer-reviewed counterpart: Rougier 2014, ten simple rules for better figures.
  • Null baseline: the figure as most repositories draw it today: text art in a code block, no alternative text, no source line.
  • For diagrams of systems, the baseline stays the one held in system-diagrams (the C4 guidance and its review checklist).

Why this one

Reason Urban 2025
Public, dated, versioned yes: dated 2025-08-27, previous version linked
Scored 13 of 20, above the threshold of 10
Rules a program can check source line, fewer than seven categories, alt text, contrast (titles are to be concise, with no length stated)
Accessibility included WCAG 2.0 AA contrast for text and alt text for web charts
Rival considered FT 2026 (11 of 20) chooses chart types and gives no layout rules; Rougier 2014 is expert advice with no experiment, and few of its rules have a threshold (a caption on every figure is checkable)
Weakness no study cited; made for charts more than for diagrams

What the new figure shape is compared on

Property Urban 2025 Evidence in this strand
Title that states the message yes Borkin 2016, Rougier 2014
Source line yes none; convention
Direct labels yes, when possible; otherwise a legend across the top none for direct labels; Huestegge 2011 tested data-legend compatibility
Colour restraint yes (fewer than seven categories) W3C 2023c (held); Song 2025 found colour raised credibility against grayscale and cartoon bars lowered it, so it does not support restraint
Alternative text yes W3C 2023e, W3C 2026a
Contrast of lines and fills WCAG AA, text only W3C 2023g adds 3:1 for graphics
Drawn from source, not typed not covered W3C 2023a, Mermaid 2026c
Crossings and angles not covered Purchase 1997, Huang 2008b
Long description not covered W3C 2026a
  • The new shape adds three rows the baseline lacks: drawn from source, crossings and angles, long description.
  • The comparison is by checklist on the same figures: a sample of the family's existing text-art diagrams, drawn again and scored on each row.
  • No outcome test with readers is planned or implied; none of the rows above has one for diagrams.

Status

  • The review is finished for Q11a to Q11d, because a baseline is named.
  • Q11e is a first pass: newsroom guides were not opened (see protocol.md).