Most SEO plugins give you a score. Rankavia gives you one score with four parts, and each part answers a different question about your page: can search engines read it, can answer engines quote it, can generative engines trust it, and does it load fast enough for anyone to care.
What the four parts measure
Search engines covers the classics: one title of a sensible length, a meta description, a canonical URL, a single H1, robots directives that do not contradict each other, and structured data that validates. These are the checks every crawler has run for a decade, and they still decide whether a page is indexed cleanly.
Answer engines looks at the page the way ChatGPT, Perplexity or Copilot do when they need a quotable sentence. Is the answer stated plainly near the top? Are there headings phrased as questions? Is the author identifiable? Is the date visible? None of this is magic; it is the difference between a page that can be cited and one that has to be paraphrased.
Generative engines is about depth and trust: does the page cover the sub-topics a reader would ask next, does it cite sources, does it carry original data or examples, and is the HTML semantic enough that a model can tell the article from the sidebar.
Speed is Core Web Vitals, measured the way Google measures them. A slow page loses the visitor before any of the above matters.
Why one number
Because the people who own sites are not SEO specialists, and the four areas pull against each other if you optimise them separately. A page stuffed with schema can still be unreadable to an answer engine. A fast page can have no title. The Visibility Score forces the trade-offs into view and tells you which single change moves the number most.
The score is a measure of what we can see from the outside. It does not promise rankings, and no tool honestly can. What it does promise is that every red item on the list is something you can fix today, and that the free scanner on rankavia.com and the plugin dashboard will agree with each other about it.