For content

Headings, link text, alternative text and plain language, checked while you write rather than at audit.

What we guarantee

Very little, and that is the point of this page. Almost nothing about accessible writing can be enforced by a component. What the system does provide:

A structure that makes correct headings the easy option. Every page kind in these docs has a fixed heading outline, and assert-ia.mts fails the build if a page invents a heading its kind does not have or skips one it does. That is a documentation-site guarantee, not a product guarantee, but it is the same discipline we are asking you to apply.
A vocabulary you do not have to invent. The plain-English A to Z is the canonical clinical-to-plain mapping and is machine-readable, so the same replacement is used in your UI, in your help content and in Term.
Copy rules that are versioned like code. Everything under Content and language is part of the system, not a style suggestion, and changes to it appear in the changelog.

Heading structure. One h1 per screen, no skipped levels, and headings that describe the section rather than decorate it. Screen-reader users navigate by heading more than by any other mechanism; a screen whose headings read "Overview / More / Details" is a screen with no navigation.

Link text that works out of context. Assistive technology can list every link on a page. "Read more", "here" and "click here" are indistinguishable in that list. Write the destination: "Read how we calculate your range".

Alternative text for anything that carries data. A ScoreDial is a picture of a number. A RangeBar is a picture of a comparison. Both need a text equivalent that gives the same answer, and neither is served by alt="score dial". The method is on Alt text and descriptions.

Plain language, especially under stress. A reader who has just been told their result is outside the expected range has less working memory available than they had a minute earlier. Reading age is not a vanity metric here. See Health literacy.

Error and empty copy. The words in a failure state are accessibility content: they must say what happened, whether the reader's data is safe, and what to do next. See Error and empty messages.

How to check

List the links

Extract every link on the screen into a flat list with no surrounding text. If two links have the same text and different destinations, or if any entry does not say where it goes, rewrite it.

List the headings

Do the same for headings, in order, with their levels. Read the list aloud. It should work as a table of contents for the screen. If it does not, the screen's structure is wrong, not just its wording.

Read every number out loud

"BP 132/84 mmHg" is read by a screen reader as something close to "B P one hundred and thirty two slash eighty four m m h g". Decide whether that is acceptable, and if it is not, supply the spoken form. The formatting rules are on Grammar and mechanics and the clinical rules on Numbers, units and precision.

Cover the picture

Hide every chart, dial and icon on the screen and read what remains. If the screen no longer answers the question it was built to answer, the missing answer is the alternative text you have not written yet.

Check the reading level, then ignore the score

Run a readability measure over the copy to find the sentences that drag it up, then fix those sentences rather than the score. Why the number is a diagnostic and not a target is on Reading level.

Measured results

This table has not been generated. It is produced by scripts/check-freshness.mts. Run pnpm run generate and reload.

Nothing on this site types a measured number by hand, so an ungenerated table shows this rather than an example.

Readability is measured per page rather than per corpus, and no corpus-wide measurement is published. The freshness report tells you which content pages are past their review date; it does not score their prose.

Known gaps

No readability measurement runs in CI. <ReadingLevel> is a P2 component and is not yet implemented, so the check above is manual.
The plain-English A to Z is small. It is authored from scratch, because the NHS A to Z is Crown copyright and cannot be reused, so it grows one original entry at a time.
There is no guidance for translated content, and the reading-level advice here is written for English. See Internationalisation and RTL.

Updates to this page

Last read through against the system on 2026-09-02. Due for review every 6 months; expiry is reported by pnpm run check:freshness.