Glossary
What is data labeling?
Data labeling turns raw records into examples a model can learn from; here is what it adds and which buyers pay for it.
Updated
Definition
Data labeling is adding information to raw records, such as a category, an outlined object, a transcript or a ranking of answers, so a machine learning model can learn what a correct output looks like. The labelled set is often called ground truth.
What a label is
A model learns by comparing its guesses with the right answers. Labels are those answers. AWS describes the labelled set as the ground truth that a model's accuracy depends on, and gives examples by data type: boxes or pixel outlines around objects in images, sentiment, intent and named entities in text, and transcripts and tags for audio.
Labels for language models
Language models brought new kinds of label. In OpenAI's InstructGPT work, people wrote demonstrations of the desired answer to a prompt, used to fine-tune the model, and then ranked several model outputs from best to worst, used to train it further with reinforcement learning. A written answer or a ranking is a label too, just a more expensive one.
Raw or labelled: who buys which
| What is sold | Typical buyer | What the labels add | What the seller must prove |
|---|---|---|---|
| Raw records: documents, logs, code history | Teams training broad models, or buyers with their own labeling pipeline | Nothing yet; the buyer decides what to label | Rights, volume, coverage and that personal data is removed |
| Records with outcomes already in them: a ticket and its resolution, a claim and its settlement | Teams tuning or testing a model on a specific task | A real-world answer recorded at the time, not added later | That the outcome field is accurate and filled in consistently |
| Purpose-labelled sets: categories, boxes, transcripts | Builders of classification, vision and speech models | Ground truth for one defined task | The labeling guidelines and how often labelers agreed |
| Demonstrations and preference rankings | Language model post-training teams | Examples of good behaviour and judgements between answers | The expertise of whoever wrote or ranked, and consistency |
The second row is often overlooked. Many business records carry labels already, because people recorded what happened: the fix that worked, the diagnosis that was confirmed, the invoice that was disputed.
Outcomes already in the records
That pairing of input and real outcome can be worth more than labels added afterwards, because nobody had to guess. It can also serve as an evaluation set, a test with known answers.
How data labeling gets done
- People label each item, often with several labelers per item and their answers combined, which AWS calls labeler consensus.
- A model labels the items it is confident about and sends the uncertain ones to people, whose answers then improve the model. AWS describes this as human-in-the-loop or active learning.
- Labels come from the records themselves, when the system that produced the data also recorded an outcome.
What buyers will ask
Whichever method is used, buyers will ask how it was done. The EU AI Act's Article 10 lists annotation, labelling, cleaning, enrichment and aggregation among the data-preparation steps that providers of high-risk AI systems must account for, and asks that training, validation and testing sets be relevant, representative and, as far as possible, free of errors.
Should an owner label data before selling it?
Usually not until a buyer says what it wants. Labels only help if they match the buyer's task and categories, and a lab with its own scheme may relabel everything anyway.
Spend first on what every buyer needs: clear rights, removal of personal data, consistent formats and documentation of what each field means, which is closer to cleaning and enrichment than to labeling. Then value the dataset as it stands and ask buyers whether labels would change the price.
Where DataBroker fits, and where it doesn't
DataBroker doesn't label data, run a labeling service or offer labeling work. We help brokers and data owners decide what a dataset is worth as it stands, whether existing outcome fields make it more valuable, and how to license it. If you need a labeling vendor, look elsewhere.
Sources
3 sources · checked Nov 9, 2026
- AWS: What is data labeling?Definition, ground truth, label types by data, labeler consensus, human-in-the-loop · Checked
- Ouyang et al., Training language models to follow instructions with human feedback (arXiv 2203.02155)Labeler demonstrations and rankings of model outputs · Checked
- EU AI Act, Article 10: Data and data governanceLabelling among data-preparation steps; quality expectations for training, validation and testing sets · Checked
Data labeling FAQ
Is labelled data worth more than raw data?
Only when the labels fit what the buyer is building. Accurate labels for the buyer's task save it time and money; labels in the wrong scheme add little. Outcomes recorded at the time, such as how a case was resolved, tend to be the most useful.
What is the difference between data labeling and data annotation?
The terms are mostly used interchangeably. Some teams use annotation for richer markup, such as outlining objects or marking spans of text, and labeling for assigning a category, but there is no fixed rule.
What is ground truth in machine learning?
The set of answers treated as correct, against which a model is trained and checked. If the ground truth has errors, the model learns them and its test scores mislead.
Do AI labs buy unlabelled data?
Yes. Large text, code and document archives are often bought unlabelled, because the buyer adds its own labels or uses the data for pretraining, where labels are not needed.
Related
- AI dataset
An AI dataset is the material a model learns from: what it contains, how it is organised, and what buyers check before licensing one.
- Data enrichment
Data enrichment adds context a dataset lacks, from outside sources or from analysis, so it answers more questions than it could alone.
- Data valuation
Data valuation explained for people selling or brokering a dataset: three standard methods, what each misses, and a worksheet to score one.
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