Accessibility score calculation

Based on whether an accessibility rule is applicable, passed, or failed, a multiplier is assigned as follows:

A rule is considered:

• Applicable when the rule is selected for the report and at least one element in the report is assessed against it.
• Passed when no element assessed against the rule has failed.
• Failed when at least one element assessed against the rule has a confirmed violation. Experimental rules are included in the score calculation.

Based on the severity of each accessibility rule, a score is assigned as follows:

The total passed score (P) and failed score (F) are calculated using the following formulae:

For each applicable rule i from 1 to r,

Impact of passed rules on score = P = Σ(Severity_i × Applicable_i × Multiplier_i)

Impact of failed rules on score = F = Σ(Severity_i × Applicable_i × Multiplier_i)

With a multiplier of 2 applied to failed rules, failures are penalized twice. The effective score values are:

Minor: 2, Moderate: 6, Serious: 14, Critical: 20

The accessibility score for a report is calculated using the following formula:

Accessibility score = [P / (P + F)] × 100

Where:

• A score of 100 means all applicable rules passed.
• A score of 0 means all applicable rules failed.
• If no rules are applicable to the report (P + F = 0), the score is not calculated.