training data

basicwidespread

Training data are the examples – texts, images, audio, numbers – from which artificial intelligence learns what it later knows.

In plain terms

Artificial intelligence is not made by someone writing down what to do rule by rule. Instead, it is shown countless examples, from which it filters out patterns itself. These examples are the training data.

It is like when a child learns what a dog is: no one gives them a definition, they just see many dogs, and suddenly they recognize one they have never met before. However, if they have only seen dachshunds, they will hesitate with a St. Bernard. The machine can only generalize from what has been presented to it.

That is why they say the model is only as good as its data. The quantity, quality, and composition of the training data determine where the system will be strong, where weak, and what biases it carries.

Training data is different from what you type into a chatbot. The model acquires its knowledge from the former during training, while the latter is used only within that specific conversation.

How it works

Collection: developers gather raw materials, such as websites, books, images, audio recordings, program code, or company records.
Cleaning and labeling: they filter out erroneous, duplicate, or harmful content, and where needed, humans mark what is visible or readable in each example (for example, 'there is a cat in this image').
Splitting: the model trains on the majority of the data, while a smaller, reserved portion is used to verify whether it can handle examples it has not seen before.
Training: the model repeatedly goes through examples, guesses, and gradually adjusts its internal settings based on its mistakes until its guesses are good enough.
Closure: the finished model does not store copies of the data, but the patterns distilled from them, and its knowledge roughly ends where the collection of training data finished.

An everyday example

You ask a chatbot about last week's news, and it replies that it has no information on the matter, or confidently states outdated data. This is because its training data was closed months or even more than a year ago, and it only knows what has happened since if it can search the internet in the meantime.

Who is affected

everyoneWhat you publish publicly on the internet can become part of a model's training data, and the models' responses stem from this data.

entrepreneur, executiveYou need to know whether the AI service you use uses your company data for training, because trade secrets and customer data may be at stake.

lawyer, citizenOne of the most controversial issues today regarding copyright and data protection is on whose works and data it is permissible to train a model. → Law

developerThe reliability of a model or agent largely depends on the data it was trained on; therefore, without knowing the data, you cannot assess its limitations. → Code

A common misconception

MythArtificial intelligence is a massive database from which it retrieves learned texts.

In realityThe model does not store or retrieve the training data, but generates new answers based on patterns learned from them. It sometimes returns a frequently seen text passage verbatim; this is rare but is the subject of copyright disputes.

Limits and risks

If the training data is one-sided or biased, the model will be too: it adopts existing biases in the data and can even amplify them.
A model's knowledge stops at the cutoff date of its training data; it does not know about newer events without a separate search.
The exact composition of training data for large models is mostly not public, making it difficult to verify externally what they learned from.
Before entering confidential data into an AI service, check the settings to see if your conversations are used for future training, and if possible, disable this.

Similar, but not the same

tesztadatok – Test data are intentionally withheld from the model during training because these are used to measure how well it handles unknown examples.
prompt – A prompt is what you type into the model during use; it does not directly change the model's knowledge, only guides the specific response.
knowledge base – The system retrieves fresh information from the knowledge base when answering, while training data is embedded into the model during training and can only be modified later with further training.

Related concepts

Broader

machine learning, dataset, model training

Narrower

labeled data, synthetic data

On the edge

validation data, tesztadatok, bias, fine-tuning, data labeling, knowledge cutoff, large language model

A brief history

The idea of a machine learning from examples is as old as machine learning itself; Arthur Samuel popularized the term "machine learning" in 1959. One of the most important milestones of the era of large training datasets was ImageNet, introduced in 2009, containing millions of labeled images.

Where things stand

By the end of 2026, every machine learning-based system will rely on training data, and the debate centers on whose content and under what conditions it is permissible to train on. The EU AI Act already requires providers of general-purpose models to publish a summary of the training data used.

Status: 2026 November

In the news

Appears in 8 Agent Age stories; the curve shows weekly occurrence in the news magazine.

LG AI Research tool checks copyright risk in training data 45 times fasterNov 4, 2026 · Jog
Thomson Reuters v. ROSS: Third Circuit recognizes licensing market for AI training dataOct 27, 2026 · Jog
Factory AI's valuation triples in five months to $5 billionOct 12, 2026 · Code
ANI v. OpenAI: Indian analysis of AI training and fair dealingOct 6, 2026 · Jog
California enacts more than two dozen privacy and AI laws in 2026 sessionOct 5, 2026 · Jog
IFR: about 7,000 humanoid robots sold in 2025, mostly for research and data collectionSep 21, 2026 · Ipar
US government sides with OpenAI in copyright dispute as Zuckerberg opposes national AI regulatorSep 2, 2026 · Agent Age
Agile Robots brings physical AI to factories and collects robot training dataSep 1, 2026 · Ipar

Also known as

training data · training data · training data · training data · training set · training data · training set · training dataset

Sources

Wikipedia: Training, validation, and test data sets

This entry was machine-edited and has undergone machine expert review; the “In the news” section updates automatically from Agent Age stories.