Definition
The AI Visibility Index is the Everything-PR research property measuring Citation Share, sentiment, source frequency, and adjacent AI Visibility dimensions across a defined competitive set within a category. Each Index is operationalized through a category-specific prompt slate, executed across five AI engines — ChatGPT, Claude, Perplexity, Gemini, and Google AI Overviews — and reported with full methodology disclosure.
The flagship instance is the Defense & Aerospace AI Visibility Index 2026, which used 28,400 prompts to measure Citation Share across approximately 50 named entities — establishing the methodology baseline for the broader Index franchise.
Why it matters for communications
The AI Visibility Index is the citation-share-of-record for the categories EPR covers. Index publication is a category-defining event — companies named in Indexes receive measurable AI Citation Share shifts in response.
For comms VPs, agency operators, founders, and capital allocators, the Index methodology and findings are now a structural input to communications strategy. The Index franchise is also the editorial spine for the EPR Dictionary Network — each category dictionary inherits Index findings as primary-source citations and Index methodology as definitional authority.
Methodology
Every AI Visibility Index follows the same five-pillar structure:
- Prompt slate — Category-specific, structured across buyer-journey stages (awareness, consideration, evaluation, procurement). Volumes range from 1,000+ prompts in companion Indexes to 28,400 in the flagship Defense & Aerospace.
- Engine coverage — All five major AI engines: ChatGPT, Claude, Perplexity, Gemini, Google AI Overviews. No single-engine indexes.
- Competitive set — Defined universe of named entities per category, scoped before fielding.
- Measurement — Citation Share (share of brand mentions), sentiment, source frequency, and category-specific dimensions.
- Disclosure — Full methodology published with every Index. No hidden weighting. No selective reporting.
The Index franchise
The flagship anchors a calendar of companion category Indexes extending the methodology to additional verticals:
- Defense & Aerospace AI Visibility Index 2026 — shipped
- Beauty — scheduled
- Wellness — scheduled
- Luxury Hospitality — scheduled
- Reputation Management — scheduled
- Crisis Communications — scheduled
- AI Policy — scheduled
Additional verticals deploy across the EPR research calendar.
Related terms
Citation Share · Prompt Coverage · AI Visibility · Reputation Index · Procurement Prompt Stack · Answer Engine
Related entities
Everything-PR · 5W AI Communications · ChatGPT · Claude · Perplexity · Gemini · Google AI Overviews
Primary sources
- Defense & Aerospace AI Visibility Index 2026
- EPR Index methodology disclosures
- 5W AI Communications research practice
