Scoring

The formula

penalty_raw     = Σ (severity_weight × issue)  per criterion, capped at MAX
scaleFactor     = 1 / (1 + log10(files_scanned))
penalty_scaled  = penalty_raw × scaleFactor
score           = round( 100 × exp(-k × penalty_scaled) )

With k = 0.02 and MAX_PENALTY_PER_CRITERION = 15. The curve is asymptotic — no scan ever scores exactly 0.

Severity weights

Critical issues cost 10× more than minor ones. Two critical issues outweigh twenty minor ones.

Density scaling

Without scaling, a 1,000-file repo with 10 issues would score worse than a 10-file repo with 10 issues — even though the first is clearly healthier relative to its size. The scaleFactor divides the raw penalty by 1 + log10(files), flattening the difference.

Per-criterion cap

Without a cap, a single spammy rule (say, 200 missing alt attributes) would dwarf every other issue. MAX_PENALTY_PER_CRITERION = 15 means the same criterion can contribute at most 15 penalty points, regardless of occurrence count. Adding a 201st missing alt to the same criterion costs nothing — the score is already maxed out on that one.

Conformance level

Separately from the score, Equall computes a WCAG conformance level: None, Partial A, A, AA, or AAA. The rule:

• Any Level A violation → Partial A
• Zero Level A, any Level AA violation → A
• Zero Level A and AA, any Level AAA → AA
• All clean → highest level the scan covered

Best-practice issues (no WCAG mapping) never affect the conformance level — they only appear in the Best-Practice Recommendations section of the output.

POUR breakdown

Every WCAG criterion belongs to one of four principles — Perceivable, Operable, Understandable, Robust. The POUR breakdown runs the same formula isolated to each principle, giving four sub-scores. Principles with no covered criteria show n/a.