Citation Gap Index

Definition

Citation Gap Index (CGI) — a measure of how invisible a market category is to AI engines. It combines two figures measured over the same tracking window: the share of companies in a category receiving zero AI citations, and how concentrated citation events are among the top few players. A high score means most competitors in a category are structurally absent from AI engine answers, while a small handful capture nearly all the citation volume.

The index is reported as a pair — zero-citation rate / top-5 concentration — rather than a single blended number, because the two figures describe different failure modes: a category can have low zero-citation rate but still be highly concentrated, or vice versa.

Calculation formula

For a tracked category over a given window (Kaus AI uses a rolling window against ChatGPT, Perplexity, Gemini, and Claude):

Both inputs are counted from the same set of daily buyer-intent queries run across the four tracked AI engines, over the same date range, for the same list of companies in the category.

Data example — GEO/AEO category, 14 July 2026

Zero-citation rate across 82 tracked GEO/AEO companies, updated monthly from Kaus AI's GEO Engine Monitor.

Citation concentration: the top 5 companies vs. the remaining 77 tracked companies.

Methodology

Kaus AI's GEO Engine Monitor queries ChatGPT, Perplexity, Gemini, and Claude daily with buyer-intent questions in a given category, logs every company mention across responses, and computes: (a) the share of tracked companies with zero mentions, and (b) the share of citation events captured by the top 5 most-cited companies. The list of tracked companies per category is fixed at the start of a window to avoid selection bias as new entrants appear.

Full methodology and findings: see the GEO Visibility Gap Report, or the Complete Guide to AI Citation Building for what to do about a high score.

Reading history

The Citation Gap Index was first published on 11 June 2026 using a 28-day window (14 May – 11 June) that scored 66% / 86% for the GEO/AEO category. Kaus AI's tracking pipeline has kept running since, and the 14 July reading above reflects the fuller cumulative dataset. Both readings are genuine — the index is a live measurement, not a fixed claim, and Kaus AI publishes the current number each time it refreshes rather than keeping the original figure static.

Frequently Asked Questions