Introducing the 2023 Silktide Index

The new Silktide Index launches in January 2023. It includes enhanced accessibility testing and WCAG 2.2 support.

Over the past couple of years, Silktide’s website testing and scoring methodology has evolved. We now test for more issues and in some cases, test in different ways. We’ve upgraded some score weightings to reflect the importance of various accessibility issues. WCAG 2.2 accessibility testing is now included.

We’ve updated the Silktide Index to reflect these changes and advances in technologies.

What does this mean for you?

In short:

  • Silktide Index now includes WCAG 2.2 checks
  • Accessibility tests now match the Silktide platform
  • Scores will change, some dramatically so

Why are the scores changing?

The approach for calculating scores is fundamentally different between the older version of the Silktide Index and the new one. You should not expect scores between the versions to match.

Think of it like how schools change their grading system each year. You can compare the grades of one child from 2010 with another in 2020, but they won’t (and can’t) be the same, as the criteria change.

There’s not a simple explanation for what has changed – there are new criteria, new concepts, and new approaches. For a technical explanation of the Index algorithm changes please visit this support article.

If you are a paid Silktide customer, you can expect the scores in the Index to differ from those in your account. Here’s an article that explains why Index scores differ from Silktide customer accounts.


Broadly speaking, these changes:

  • Improve scoring accuracy
  • Bring some accessibility areas up-to-date
  • Allow for more accurate identification of issues
  • Add WCAG 2.2 success criteria
  • Bring scoring between the Silktide Index and our customer’s reports more closely together

Things to consider

The following points have not changed since the previous Silktide Index but they are worth highlighting here:

  • In most cases, we are testing a sample of up to 125 pages
  • Those pages are unlikely to be the same each month
  • Any ‘decisions’ made in your own report (if you are a customer) are not applied to the Index

What other changes are being made?

In order to expand the Index, we’re streamlining some categories during 2023. We’ll combine multiple similar categories together. A specific example is the combination of all UK NHS websites into a single category.

Later in 2023, we’ll expand Silktide Index to include non-accessibility checks.

What to do next?

In January, Silktide Index will be updated and websites in all categories are likely to see changes in scores and position. This is not something to be alarmed at, but we appreciate that this kind of thing can cause some concern.

Consider this. If your score does change dramatically, check your Silktide Index report to see if new accessibility issues are highlighted. It’s likely with the new and amended testing methodology that there are accessibility problems being found that could not be found before.

Also, the score weighting has changed. Some issues may have become more important, or less important, than in previous reports.

The biggest single change is the inclusion of WCAG 2.2 testing. It’s likely that accessibility issues will be found against the new Success Criteria, which will affect scores.

If you have any specific concerns, then do reach out to us at and we’ll do our best to address them.

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