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Glossary LLM (large language model)

What is an LLM (large language model)

Definition

An LLM, or large language model, is a statistical system trained on large volumes of text that produces answers by calculating, piece by piece, which continuation is most probable according to the patterns fixed in its parameters.

On this page 5
  1. What large language model means
  2. How an answer is produced
  3. Why it matters
  4. Good practice
  5. Common mistakes
In brief

An LLM calculates probable continuations instead of querying a record, and that difference produces invented details, varying answers, and the delay with which it reacts to changes in your company.

What large language model means

The adjective “large” describes scale, not quality: the volume of text used in training and the number of parameters adjusted during that process. A parameter is a numeric value inside the network. Its count gives no basis for deducing how useful the system will be on a specific task, and vendors now hardly ever publish it.

Three things that get mixed up in everyday conversation are worth separating. The model is the parameter file plus the code that runs it. The assistant is the product around it: interface, fixed instructions, conversation history, tools. And AI search is a third layer, where the assistant queries a web index before composing an answer. The same question can come out differently at all three.

The other important distinction is temporal. A model is trained on texts up to a cutoff date. Some vendors publish two dates: the one for the training material and an earlier one up to which they consider the information reliable. After that point the parameters hold nothing about your new office, your price change or your rebranding. A system with live retrieval avoids part of the problem because it queries sources at the moment of answering, and it therefore reacts to new facts differently than an isolated model.

How an answer is produced

Text enters split into units called tokens, which can be a word, a fragment of a word or a punctuation mark. From that sequence the system calculates a probability distribution over the next token, selects one, appends it to the sequence and repeats the operation. The complete answer is the accumulation of those successive decisions.

The selection does not always land on the most probable token. Sampling parameters such as temperature or top-p govern how much accumulated probability enters the draw. At temperature zero the maximum is always taken, and even so two identical calls can diverge: on inference servers the result depends on the size of the batch each request is processed in, and that batch shifts with the load at that instant. In one experiment with a thousand generations of the same text, eighty variants appeared, all identical up to token 103.

The invented statement comes from the same place. There is no query against a database, there is a calculation of a plausible continuation. If barely any material exists about a small brand, the statistically reasonable continuation can be an office, a founder or a product range that never existed, written with the same confidence as a correct detail. Work from OpenAI also points to evaluation methods: when answers are scored as right or wrong, a model that always ventures something scores better than one that flags the lack of a basis, so the procedure rewards guessing.

Why it matters

The first consequence concerns measurement. If the same prompt can return different answers, a single check says nothing about your brand's visibility. It takes repetition, counted frequencies and mention rates over time. Anyone showing a screenshot as proof is showing one throw.

The second concerns content. Because the answer is built by probability rather than by querying a record, company details that appear only once, inside a PDF or embedded in an image, weigh little against those repeated consistently across many citable sources. That turns consistency of name, address, product range and figures into a technical question rather than a cosmetic one.

The third concerns error correction. When a system attributes something false to your company, there is no edit button. Only the available material can be altered: publish the correct version where the system can reach it, get weighty sources to pick it up, and wait for the next training cycle or, with live retrieval, for the next indexing pass. Knowing which of the two cases you face decides whether the fix takes days or months.

Good practice

  • Repeat each query several times and record in how many runs the brand appears, instead of trusting a single answer.
  • Record the model, the date and whether the answer carried linked sources alongside every measurement. Without those three details the later comparison is worthless.
  • Publish company details as plain text and in the same format everywhere: legal name, address, product range and figures with their date.
  • Distinguish in the report between systems with live retrieval and models without web access, because the time until a correction takes effect differs.
  • Sample-check what the systems claim about your company and keep dated screenshots, especially before a price or location change.
  • Treat every LLM statement about figures, dates or regulation as unverified until one of your own sources confirms it.

Common mistakes

  • Reading a favourable answer as a position won, when the next call may return something else.
  • Comparing measurements from different moments without recording the model version, which the vendor changes without notice.
  • Using the parameter count as a quality argument, when that figure says nothing without a task and a measurement method.
  • Assuming that a correction published on your site today shows up tomorrow in a model without live access.
  • Asking the system for the source of a statement and taking it at face value: the reference can also have been generated by probability.
Manuel Riveiro Rodriguez CEO & Digital Strategist

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Frequently asked

Why does an LLM give different answers to the same question?

Because the answer is drawn from a probability distribution, and because the calculation on the server depends on the size of the batch of requests processed at once. That batch varies with load. Even at temperature zero, two identical calls can part ways from a certain point in the text onward.

Can I correct what a model says about my company?

Not directly, because there is no editable record. What can be changed is the available material: publish the correct version on your site, get weighty sources to pick it up, and wait for the next training run. On systems with live retrieval the effect arrives much sooner.

What does the training cutoff date mean?

That the parameters hold no material later than that day. Some vendors also publish an earlier date up to which they consider the information reliable. Everything your company changes afterwards stays outside until the next cycle, unless the system queries live sources while answering.

Does an LLM search the web while answering?

It depends on the product. A model called through an API answers from its parameters alone unless tools are connected. Consumer assistants and AI search usually retrieve documents before composing. Check it case by case, because the time it takes to react to your changes depends on it.

Is the parameter count useful for choosing a model?

Barely. It is a measure of size, not of usefulness, and says nothing without a specific task and a measurement method. Vendors also hardly publish that figure for their current models any more. The useful comparison runs on your own queries and your own criteria.

Sources

  1. The paper introducing the Transformer architecture, the basis of today's language models and of the attention mechanism that weights context.
  2. OpenAI's analysis of why invented statements arise: evaluation methods score a model that ventures an answer higher than one that flags the lack of a basis.
  3. An experiment explaining variation between identical calls: a thousand generations of the same text at temperature zero produced eighty variants, caused by batch-size dependence on the server.
  4. Vendor documentation distinguishing the training-data date from the date up to which the information is considered reliable.
  5. The paper describing retrieval-augmented generation, the procedure by which a system queries external sources before composing an answer.