DefinitionIn forcev1.0.0

Validation data

Data with which you evaluate and tune the trained system, including its non-learnable parameters, to prevent underfitting and overfitting. Meant for tuning, not for producing the final score.

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Address and citation

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Identifier: praxikon:eu:ai-act:definition:definitie-validatiedata
Payload hash (sha256): 4771ce3b2faa0f52b26fd42f2d915c301b392c7f3d128ff560c4183e2a98868c

Citation line

Praxikon, "Validation data", praxikon:eu:ai-act:definition:definitie-validatiedata@1.0.0, dataset praxikon:sys:registry:dataset:ai-act-implementation-graph 2.1.0 (schema 1.4.0), effective_at 2026-08-08T00:00:00.000Z, known_at 2026-08-14T00:00:00.000Z, sha256 4771ce3b2faa0f52b26fd42f2d915c301b392c7f3d128ff560c4183e2a98868c

Version: 1.0.0
Legal time (effective_at): 8 August 2026
Knowledge time (known_at): 8 August 2026
Closed on: Not closed
Application date: 1 August 2024
Topics: definitions

Review status: Placed against the official source (8 August 2026). Next check due by 4 February 2027. The check date is the knowledge date of this version; no later recheck has been recorded.

What this object links to

Every relation appears below as a path: from the source with its locator, through the conditions and exceptions of the object carrying the relation, to the consequence. A locator belongs to a statement in the data and not to a relation, so the source is the source anchor of the carrying object.

What this object is about

1 of 1 shown

The object is about this role. Undifferentiated: it does not follow that the duty rests on this role.

Source
Official fact on this object, with its locator.
- EU Artificial Intelligence Act 2024/1689
  Locator: Article 3(30)
  praxikon:eu:ai-act:source:reg-eu-2024-1689
  Open official source
Via
No condition or exception recorded on this object.
Consequence
- ActorProvider of an AI system
  praxikon:eu:ai-act:actor:provider

What this object states

Official fact

Attributable to a named primary source, with a locator. Where they differ, the official source prevails.

Article 3(30) defines validation data as data used for providing an evaluation of the trained AI system and for tuning its non-learnable parameters and its learning process in order, inter alia, to prevent underfitting or overfitting.
- Locator: Article 3(30)praxikon:eu:ai-act:source:reg-eu-2024-1689Open official source

Our interpretation

Our own reading. It can change without the law changing, and it is not the position of a supervisory authority.

The legislator deliberately separated validation from testing, because the classic error is using the same data both for tuning hyperparameters and for reporting final performance. You then measure your own choices back and overstate accuracy, while Article 15 requires a realistic level of accuracy that is stated in the instructions for use. In supervisory conversations this is one of the first things that stands out: an impressive accuracy figure without a separate, untouched test set.
- Locator: Article 3(30)praxikon:eu:ai-act:source:reg-eu-2024-1689Open official source

Recommended step

A practical step we consider appropriate. Not an obligation following from the Regulation.

Record which tuning decisions were made on validation data, how many evaluation rounds took place and which configuration was ultimately chosen. Ensure the validation data are never used for the figure you cite in the instructions for use and the technical documentation.
- Locator: Article 3(30)praxikon:eu:ai-act:source:reg-eu-2024-1689Open official source

When this applies

No condition recorded on this object.

When this does not apply

No exception recorded on this object.

Referring to this object

Citation block

Copy this reference into your advice, article or file. The identifier, the version and the hash keep the statement findable later, even once the dataset has moved on.

Reference

Praxikon, "Validation data",
praxikon:eu:ai-act:definition:definitie-validatiedata@1.0.0,
dataset praxikon:sys:registry:dataset:ai-act-implementation-graph 2.1.0 (schema 1.4.0),
effective_at 2026-08-08T00:00:00.000Z, known_at 2026-08-08T00:00:00.000Z,
sha256 4771ce3b2faa0f52b26fd42f2d915c301b392c7f3d128ff560c4183e2a98868c,
https://www.praxikon.com/en/verkenner/definition/definitie-validatiedata
(https://www.praxikon.com/api/v1/entities?id=praxikon%3Aeu%3Aai-act%3Adefinition%3Adefinitie-validatiedata&effective_at=2026-08-08&known_at=2026-08-08&lang=en, accessed 2026-08-25)

Short form

praxikon:eu:ai-act:definition:definitie-validatiedata@1.0.0 (sha256 4771ce3b)

BibTeX

@misc{praxikon-eu-ai-act-definition-definitie-validatiedata-1-0-0,
  author       = {{Praxikon}},
  title        = {Validation data},
  year         = {2026},
  version      = {1.0.0},
  number       = {praxikon:eu:ai-act:definition:definitie-validatiedata},
  howpublished = {AI Act Change \& Evidence Graph, dataset 2.1.0, schema 1.4.0},
  note         = {effective_at 2026-08-08T00:00:00.000Z; known_at 2026-08-08T00:00:00.000Z; sha256 4771ce3b2faa0f52b26fd42f2d915c301b392c7f3d128ff560c4183e2a98868c},
  url          = {https://www.praxikon.com/en/verkenner/definition/definitie-validatiedata},
  urldate      = {2026-08-25},
  language     = {en}
}

CSL JSON

[
  {
    "id": "praxikon:eu:ai-act:definition:definitie-validatiedata@1.0.0",
    "type": "dataset",
    "title": "Validation data",
    "container-title": "AI Act Change & Evidence Graph",
    "publisher": "Praxikon",
    "version": "1.0.0",
    "number": "praxikon:eu:ai-act:definition:definitie-validatiedata",
    "URL": "https://www.praxikon.com/en/verkenner/definition/definitie-validatiedata",
    "language": "en",
    "issued": {
      "date-parts": [
        [
          2026,
          8,
          8
        ]
      ]
    },
    "accessed": {
      "date-parts": [
        [
          2026,
          8,
          25
        ]
      ]
    },
    "note": "dataset praxikon:sys:registry:dataset:ai-act-implementation-graph 2.1.0; schema 1.4.0; effective_at 2026-08-08T00:00:00.000Z; known_at 2026-08-08T00:00:00.000Z; sha256 4771ce3b2faa0f52b26fd42f2d915c301b392c7f3d128ff560c4183e2a98868c; retrieved_from https://www.praxikon.com/api/v1/entities?id=praxikon%3Aeu%3Aai-act%3Adefinition%3Adefinitie-validatiedata&effective_at=2026-08-08&known_at=2026-08-08&lang=en; licence https://www.praxikon.com/nl/legal/terms"
  }
]

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