Definition

Non-determinism

AI answers are non-deterministic: temperature sampling, retrieval variation, personalisation and index freshness mean identical prompts can return materially different answers.

Classic rank tracking assumes near-determinism, which is why it can get away with checking a position once a day. That assumption does not transfer.

Every methodology decision in AI visibility measurement — sampling, intervals, evidence retention — exists to manage non-determinism.

Nostimates measures non-determinism 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 Answer engine Citation Brand mention Mention rate Confidence interval Statistical significance Citation volatility 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