Definition

Answer engine

An answer engine is a search product that responds to a query with a generated answer, usually citing a handful of sources, rather than returning a ranked list of documents for the user to evaluate.

Google AI Overviews, Google AI Mode, ChatGPT, Perplexity, Copilot, Baidu ERNIE and Naver's AI surfaces are all answer engines. So are assistants embedded in products that never present themselves as search.

The commercial consequence is that inclusion replaces ranking as the unit of visibility. There is no position two in a paragraph — you are either in the answer or you are not.

Nostimates measures answer engine across twelve AI answer surfaces. Request access →

All terms

AEO (Answer Engine Optimisation)GEO (Generative Engine Optimisation)AI Overviews AI Mode Citation share n-sampling Query fan-out Grounding Share of voice (AI)Extraction success rate Surface Citation Brand mention Mention rate Confidence interval Statistical significance Citation volatility Non-determinism Reproducibility Identity-free collection Personalisation Locale Residential proxy Bot detection Collection cost Credit Evidence retention Audit trail Parser version Canary prompt Data freshness Cadence Prompt set Head term Long-tail query Competitive set llms.txt robots.txt AI crawler Training crawler Retrieval-augmented generation (RAG)Hallucination Answer box Featured snippet Zero-click search Entity Entity salience Knowledge graph Structured data JSON-LD schema.org FAQ schema Answer-first content Chunk Embedding Semantic search Prompt injection Market coverage Sentiment analysis Position tracking White-label data