Source Gap Analysis is the process of listing the specific pages AI engines cite when answering your buyer prompts, then identifying which of those pages don't mention your brand. The output is a concrete target list for GEO work.
Why it matters
AI engines assemble answers from a small pool of retrieved sources, often the same handful of Reddit threads, listicles, and review pages per prompt. If those pages omit you, the answer omits you, no matter how good your own site is. Source gap analysis flips GEO from guesswork ("publish more content") to a checklist: here are the twelve pages that control the answer, here are the eight that don't mention us. Because engines like Perplexity and ChatGPT Search show their citations, this pool is fully visible, you can read exactly what the model read.
How to use it
- For each prompt in your prompt tracking set, collect every cited URL across engines and dedupe into a source pool.
- Mark each source: mentions you, mentions competitors only, or neither, the "competitors only" pages are your brand mention gap in page form.
- Close gaps by source type: reply helpfully in the Reddit thread, pitch the listicle author for inclusion, claim and complete the review-site profile.
Related terms
Paul-Marie is the founder of Readyt, the Reddit growth platform for SaaS. He has generated 16K€+ in pre-sales in 2 months using nothing but Reddit, and now helps founders turn Reddit threads into their #1 acquisition channel.
