How to calculate it
Take a fixed set of buyer questions, collect each engine's answers, and list every source each answer cites. Citation share = citations pointing to your domain ÷ all citations in the set × 100. Count per engine, because each engine cites differently, and only count answers that actually show sources.
Citation share vs mention rate
Mention rate asks "did the answer name us?". Citation share asks "did the answer use our pages to say it?". A brand can be named often while the engine cites review sites, marketplaces or press coverage instead of the brand's own site. High mention rate with low citation share usually means your own pages are hard to retrieve, out of date, or missing the facts the engine needed.
Citation behavior varies widely by content type. An Ahrefs study of 1.4 million ChatGPT prompts found that roughly half of the URLs an answer engine retrieved were actually cited in the response, and that search-sourced content was cited 88.5% of the time compared with just 1.9% for Reddit-sourced content, showing that where a source comes from strongly shapes whether it gets cited at all.
How to raise it
Publish the pages buyers' questions actually need (comparisons, specs, pricing model, policies), keep them current with visible dates, put the key fact in the first lines under a clear heading, and make sure AI search crawlers can fetch them. Citation share moves slowly; track it monthly, not daily.
How ClerAEO measures it
ClerAEO stores every answer with the sources the engine relied on, so you can see which pages each engine cited for each question and how often your own domain is among them.