How do you formulate a site wide accessibility score? My score seems higher than I expected.

Each page's accessibility score is calculated based on the number of violations, and the number of elements affected by each of those violations. Violations themselves also have varying severity levels (Critical, Serious, Moderate, Minor). Critical violations have the largest impact on the score, and minor have the smallest impact.

Eligible pages then contribute their accessibility score to produce a site wide accessibility score. This is simply an average. All the following criteria must be met for a page to contribute its score to the site average

• The page must be actively monitored (Daily, Weekly, Monthly, or Quarterly)

• The page's last accessibility scan must have succeeded (ex: pages that 404 are excluded from the site average)

Your site accessibility score may be higher (or lower) than you anticipated due to large numbers of pages with either high, or low scores pulling the average in one direction or another.