What is citation share and why does it matter?
Citation share is the percentage of AI-generated responses to your target queries in which your brand is mentioned, cited, or recommended. If you test 100 relevant prompts across ChatGPT, Perplexity, Claude, and Gemini, and your brand appears in 34 of those responses, your citation share is 34%.
Citation share is the primary GEO metric because it directly measures what matters: whether AI engines include your brand when buyers are researching your category. A brand with 0% citation share is functionally invisible in AI search — even if it ranks #1 on Google.
Beyond raw mention rate, citation share breaks down into:
- Recommendation rate: does the AI actively recommend your brand, or merely acknowledge its existence?
- Sentiment: are descriptions positive, neutral, or negative?
- Engine coverage: citation share varies by engine — a brand can have 60% citation share on Perplexity and 10% on ChatGPT for the same queries.
- Funnel coverage: citation share at TOFU (awareness) queries versus BOFU (purchase-intent) queries often differ significantly.
Establishing a citation share baseline — before making any GEO investments — is the essential first step. Without a baseline, you can't measure whether your changes are working.