- Adjacent Coherence
- How smoothly ideas flow from one paragraph to the next.
- Alt text
- Alt text should describe the image's purpose in context, not its appearance. Decorative images use alt="" so screen readers skip them. Functional images (icons that act as links/buttons) describe the action ("Search"), not the picture ("magnifying glass"). Missing or generic alt text is one of the most common accessibility failures.
- ARIA
- ARIA (Accessible Rich Internet Applications) lets you communicate semantics that the browser cannot infer — for example, that a `<div>` acts as a button, or that a region is currently expanded. The first rule of ARIA is "don't use ARIA": prefer native HTML elements (button, label, nav, main) and only reach for ARIA when no native element fits.
- Cognitive Load Index
- Combines multiple visual analysis factors into a single number representing the mental effort required to process a page. Lower is better — aim for pages that feel clean and focused rather than overwhelming.
- Color Contrast
- WCAG requires a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text (18px+ or 14px+ bold). Low contrast makes text hard to read, especially for people with low vision or in bright environments like outdoor mobile use.
- Color Shift (ΔE)
- Delta E (ΔE) is a standard measure of perceptual color difference. A ΔE under 1 is imperceptible; under 3 is barely noticeable; over 5 is clearly different. Used here to check if your brand colors are being used consistently.
- Error Prevention
- Nielsen's fifth usability heuristic. Using HTML attributes like "required," "pattern," and "maxlength" catches input errors before submission. Inline validation that checks as the user types is even better — it prevents the frustration of submitting a form only to see errors.
- Global Coherence
- How well the overall message holds together across the entire page.
- Heading Hierarchy
- Screen readers let users jump between headings to scan page structure. If you skip from H2 to H4, that navigation breaks. Headings should reflect content structure, not visual styling — use CSS for size instead of picking heading levels for their appearance.
- Incomplete audit
- The Accessibility & Usability audit runs as a three-tier cascade. Tier 1 checks content structure and usability heuristics. Tier 2 checks page speed and baseline accessibility (contrast, labels, alt text). Tier 3 drives the page in a real browser to test keyboard navigation, focus traps, and dynamic states. Tier 3 is the most expensive stage, so it runs only when Tiers 1 and 2 pass. An audit is "incomplete" when Tier 3 did not run. The usual reasons: (1) the page failed an earlier gate, so the audit stopped early to surface the foundational fixes first (a deliberate fail-fast design, not a malfunction); (2) a stage hit a technical error, such as the headless browser timing out, the site blocking automated access, or a page script crashing. The findings that did run are still valid. Fixing the foundational issues and re-running usually unlocks the full audit.
- Information density
- Information density comes from the Shannon entropy of the text, normalised against the rough maximum for English. A low value means the writing is padded or repetitive; a very high value means it is dense and effortful to read. Most readable web copy sits in the middle of the 0-1 range.
- Predictability
- Predictability is derived from the compression ratio of the text. Copy that compresses well is repetitive and template-like, so it scores high; copy with varied sentence shapes and word choices compresses less and scores low. Very predictable copy reads as generic and is easy for visitors to skim past.
- Reading Ease
- A well-established readability score based on sentence length and how complex the words are. A score of 60-70 is the sweet spot for the web — understandable by a 13-15 year old. Higher means simpler; lower means visitors have to work harder to follow you.
- Repetition
- Repetition measures how often the same words and phrases recur across the analysed copy. A small amount reinforces key messages and aids recall. High values signal copy that leans on the same wording instead of varying it, which makes a page feel monotonous and can dilute the message.
- Revenue impact
- Revenue impact multiplies a finding's priority score by an assumed traffic volume, an average order value, and a conversion-elasticity factor (the share of conversions that friction typically costs). When your real traffic and order value are not connected to the audit, standard assumptions are used, so the dollar figure is best read as a way to compare issues against each other rather than an exact prediction. A higher number means fixing that issue is likely to return more.
- Semantic Load
- How much meaning and information the page tries to communicate at once.
- System Feedback
- Nielsen's first usability heuristic: "Visibility of System Status." When users click a button, they need confirmation the system received their action. Without feedback (spinners, progress bars, success messages), users assume the system is frozen and click again or leave.
- User Control & Freedom
- Nielsen's third usability heuristic. Every modal should have a close button, every multi-step form should have a back button, and every action should be undoable when possible. Without escape hatches, users feel trapped and abandon the page.
- Visual Clutter
- Visual clutter is the volume of competing elements (icons, badges, animations, popups) on a single screen. The fewer focal points there are, the easier visitors find what they came for. The page-level finding under the same name flags specific instances; this is the broader concept.
- Visual Complexity
- How visually busy the page is — more elements, colors, and movement means higher complexity.
- Vocabulary richness (HD-D)
- HD-D (Hypergeometric Distribution D) computes, for each word in the text, the probability it appears at least once in a random 42-word sample. Averaging those probabilities gives a length-robust score that mirrors how surprising / fresh the wording feels to a reader. Most well-edited pages score 0.7-0.9; below 0.6 suggests heavy repetition.
- Vocabulary variety (MATTR)
- MATTR (Moving-Average Type-Token Ratio) slides a fixed-size window through the text and averages the ratio of unique words to total words inside each window. The sliding window makes the score comparable across short and long pages — a plain type-token ratio drops as texts get longer just because more chances to repeat words exist. Higher values mean the writer reaches for a wider word stock; lower values indicate the same vocabulary cycling.
- WCAG
- WCAG is published by the W3C and structured around four principles: content must be Perceivable, Operable, Understandable, and Robust (POUR). It defines three conformance levels: A, AA, and AAA. Most laws and contracts reference WCAG 2.1 or 2.2 at level AA.
- WCAG AA
- WCAG (Web Content Accessibility Guidelines) defines three levels: A (minimum), AA (recommended), and AAA (enhanced). Level AA covers the most impactful requirements including color contrast, keyboard navigation, text alternatives, and form labels. It is the legal standard in many jurisdictions.
- Words before repetition (MTLD)
- MTLD (Measure of Textual Lexical Diversity) counts how many words the writer can string together before vocabulary "exhausts" — defined as the running type-token ratio falling below ~0.72. The score is the average run length. Typical marketing copy lands between 60 and 120; technical or jargon-heavy writing often runs lower because the same domain terms recur.