Make every data visualization an accessible decision contract

A chart is acceptable only when its choice, encodings, equivalent data, states, operation, and data integrity are explicit and testable.

Guidance

Before implementation, record the user question and data shape that justify the chart type. Bind each series to semantic tokens and at least one non-color cue, expose an equivalent data table, define loading, empty and error recovery, and preserve keyboard and assistive-technology access without changing or obscuring the underlying values.

Do

Record the user question, comparison task, data shape, chart choice and rejected alternatives in the design decision
Bind series to semantic color tokens plus labels, shapes, patterns or line styles that remain distinguishable without color
Provide an adjacent or user-reachable table containing the same labels, units, values, ordering and filters as the chart
Define loading, empty, partial-data and error states with status announcements and a recovery action where recovery is possible
Give interactive marks, legends and controls a logical keyboard order, visible focus, accessible names and equivalent non-pointer operation
Expose a concise chart name and summary while keeping exact values and relationships available to assistive technology
Document units, source, time range, aggregation, missing-data treatment and every non-zero axis or truncated scale

Do not

Use color as the only series, threshold or status encoding
Render a canvas or SVG chart as the sole representation of the data
Choose a chart for visual novelty when a table or simpler chart answers the task more directly
Hide inconvenient values through omitted baselines, unexplained normalization, misleading area or inconsistent aggregation
Reuse the success visualization for loading, empty, partial or failed data

Verification contract

For every chart, review the signed decision record; assert chart and table values, labels, units, ordering and filters are identical; test loading/empty/partial/error fixtures; pass automated contrast and axe checks; complete the task by keyboard and screen reader; and reject color-only distinctions or an unjustified scale/truncation.

Supporting references

Implementations and verification artifacts

No linked implementation yet.