Training data vs live search: where does an AI answer come from?

Training data is what a model learned before its knowledge cutoff; live search is what it looks up on the web while it answers, and one AI answer can draw on either or both. Every AI answer is part memory and part lookup. Which part an answer leaned on decides what you can change: a page you publish this week can reach the lookup in days, and the memory not until a newer model ships.

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What is the difference between training data and live search?

Training data is the text a model learned from before its knowledge cutoff; live search is the web results an assistant fetches while it answers. The first is frozen in the model, the second is current but only covers what the engine chose to look up.

One answer can use both: the model brings what it already knows, including which brands it associates with a category, and the search adds or removes names from what it reads.

Does an AI engine always search before it answers?

No. OpenAI's documentation says that, like any other tool, the model can choose to search the web or not based on the content of the input prompt, and that with the default setting search is optional (OpenAI API docs, read Oct 15, 2026).

In our scored sample of 215 ChatGPT engine answers, 147 ran no search at all. Those named the brand 6.1% of the time; answers that searched named it 77.9%. On the same questions asked both ways, the gap was 24.1% against 78.3% (the post).

What does this look like in a real example?

In the public Tesla example (Oct 4, 2026), Claude answered "What is Tesla?" and "Is Tesla legit?" from what the model already knew, with no sources cited: training data at work.

Google AI Overviews behaves the other way. It is built on Google Search and cited sources across its answers: youtube.com 20 times, reddit.com 15 and tesla.com once on 25 buyer questions. Memory answers and lookup answers need different fixes.

What can you change in each?

Work on the part you can reach, in this order:

  • Lookup, days to weeks: the pages engines retrieve for your questions, yours and third-party, once they are recrawled.
  • Corrections, weeks: wrong facts on your own pages and on the pages engines cited when they got you wrong.
  • New pages, months: answers to questions nobody in your category answers yet.
  • Memory, a model release away: how widely and consistently the web describes you, which training picks up only when a newer model is trained.

How does Proofsource tell them apart?

Proofsource shows the searches each engine ran next to every answer where the engine reports them: ChatGPT, Perplexity and Claude report searches, and Google AI Overviews does not (the post). An answer with no search and no sources came from memory. See Prompts.

Common questions about Training data vs live search

How long until a new page shows up in AI answers?

For engines that search, as soon as the page is crawled, indexed and retrieved for a real question, which can take days to weeks. For answers from memory, not until a newer model is trained.

What is a knowledge cutoff?

The date after which a model has no training data. Vendors publish it on their model pages; facts after it reach an answer only through search.

Can I force ChatGPT to search?

A buyer cannot in most cases; the model decides. Developers can require a search through the API, but the consumer app chooses for itself.

Why does AI describe my company as it was a year ago?

Because the answer came from training data, or from an out-of-date page it retrieved. Check whether it cited sources; if it did, fix those pages.

Related terms

Large language model (LLM)

A large language model (LLM) is an AI model trained on a very large amount of text to predict and write language, and it is the part of an AI assistant that writes the answer.

Retrieval-augmented generation (RAG)

Retrieval-augmented generation (RAG) is a method where a language model first retrieves relevant documents and then writes its answer with them in view.

Grounding

Grounding is tying an AI model's answer to outside sources, such as live search results, so its claims rest on retrieved content rather than on memory alone.

Query fan-out

Query fan-out is when an AI engine splits one question into several related searches and builds its answer from all the results.

Worked example: Tesla, public AI answers, Oct 4, 2026: Proofsource's first scan of Tesla, 25 buyer questions and 5 brand questions, one answer per question on each of four engines. A small sample from one brand, shown as an example, not a benchmark.

See where AI leaves you out, and what to fix.

See which buyer questions name your brand, who gets named instead, and what to fix. 200 answers. 25 Prompts/Question. Top AI engines. 2 days. Free. No card.

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