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Accessibility Audit Severity examples

When we do Accessibility Audits, each issue usually comes with a Severity. Here are some examples of what each one means.

Here’s a recap of the four levels. Different places and tools use different words, but most places have four levels.

  • Critical - The issue stops users from accessing content or completing a task. It does not have a workaround.
  • High - The issue causes serious problems or major inconvenience to users. It has a workaround but it is difficult and not obvious.
  • Medium - The issue causes problems or frustrations for users. It has a workaround.
  • Low - The issue causes inconvenience or irritation to users. It may not need a workaround.

The distinction between High, Medium, or Low is inherently subjective. One useful heuristic is to compare it to what the experience would be like if the issue was not present.

💁 Examples

Here are a handful of examples for each severity. It’s not an exhaustive list!

The way we usually decide on a Severity is to first decide if it’s Critical or not: does it stop a user from completing a task? If it’s not Critical, we look at how serious the problem is.

⛔️ Critical

  • Functionality is not available from the keyboard.
  • Functional image is missing text alternative. (Often in an icon-only link or icon-only button).
  • Missing accessible name for an element (when no visible label is present and no aria-label is set).
  • Incorrect accessible name for an element (when no visible label is present and the aria-label is set to the value of the field, not the name of the field).
  • Content is not accessible by screen reader (aria-hidden=“true” is used incorrectly, highlighted items in a dropdown are not announced).

⚠️ High

  • Page title doesn’t represent the page contents.
  • The visual relationship isn’t in the code (usually about semantic HTML, headings that aren’t h elements, field labels that aren’t programatically linked to their fields).
  • Focus styles aren’t visible.
  • Essential content is hidden when zoomed in.
  • Colour contrast isn’t high enough.

🗒️ Medium

  • Focus order doesn’t follow reading order.
  • Label doesn’t describe the input required.
  • Error messages aren’t helpful.

ℹ️ Low

  • Invalid markup that doesn’t affect the user experience.
  • Images that are decorative aren’t hidden from assistive technology (SVGs are missing aria-hidden=“true”
  • Best Practice issues

Prioritisation

The Severity is just one aspect of prioritisation. Other aspects might be how many users the issue affects (for example by role: user, admin, super-admin) or the user journey (for example: the main user flow, or an occasional or side flow).

Summary

Once an issue has been identified, we can figure out a Severity. First we decide if it’s Critical or not. That is: does it stop a user from completing a task?

If it’s not Critical, we look at how serious the problem is. How difficult is it to complete the task compared to how easy it is if we fix the problem?