VIEX — Visibility Exclusion Index: why search-seeded corpora underestimate algorithmic citation in generative AI engines

Formalizes VIEX (Visibility Exclusion Index): the selection bias introduced when GEO research seeds its corpora from organic search results, capturing only entities visible in both search and AI citation. Named-entity recognition over 5,544 responses (Gemini 2.5 Flash, GPT-4o, Claude Sonnet 4.6) across two verticals (enterprise management systems and hospitality). Exclusion: 51.6% (ERP) and 73.6% (hospitality) of AI-cited entities fall outside the search-seeded sample. ORCID: 0009-0004-5181-3957.