GEO-Flag Measures Generative-Engine SEO in the Wild: 8.90% of Cited Pages Are GEO-Optimized, 16.36% of Pages Modified in 2026

arXiv 2608.16824·high signalXBlueskyLinkedInCopy link

Junjie Chu and co-authors build GEOFlagBench (3,200 webpages, 400 queries, four domains, eight GEO optimizer families) and find the strongest existing detector reaches only 0.880 aggregate F1 while leaning on authorship shortcuts. Their Intervention-Paired Training raises ModernBERT from 0.862 to 0.944 F1 and worst-group accuracy from 0.725 to 0.883. Deployed against Google Search and Gemini-grounded retrieval for 1,000 real user queries across 10,095 pages, they estimate 8.90% overall GEO prevalence, rising to 16.36% among pages modified in 2026 — a direct measurement of how much of what generative search cites has been engineered to be cited.