DefinitionIn forcev1.0.0

Validation data set

The form validation data may take: a separate data set or part of the training data set, as a fixed or variable split. The law leaves the method open, but not the explainability.

The official source remains authoritative. This is general information about obligations and not legal advice. See this object on the map

Address and citation

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Identifier: praxikon:eu:ai-act:definition:definitie-validatiedataset
Payload hash (sha256): b7e609baae36b231e16a3fdde9d8681deb4529b66c942984c2c7793877d13b1b

Citation line

Praxikon, "Validation data set", praxikon:eu:ai-act:definition:definitie-validatiedataset@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 b7e609baae36b231e16a3fdde9d8681deb4529b66c942984c2c7793877d13b1b

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(31)
  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(31) defines a validation data set as a separate data set or part of the training data set, either as a fixed or variable split.
- Locator: Article 3(31)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.

This definition looks redundant but settles a concrete argument: may you use cross-validation instead of a fixed holdout. The answer is yes, because a variable split is expressly allowed. The flip side is that the burden shifts to reproducibility. If your split changes per run and you do not record the splitting rule, you cannot afterwards show that your reported performance is not the result of a lucky split. For data sets with a time ordering or with heavily represented subgroups, a random split is moreover misleading, while Article 10 specifically demands representativeness.
- Locator: Article 3(31)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 in the technical documentation which split you use, whether it is fixed or variable, which splitting rule or seed applies, and why that split suits the nature of the data. Keep this per model version, so a later retest is reproducible.
- Locator: Article 3(31)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 set",
praxikon:eu:ai-act:definition:definitie-validatiedataset@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 b7e609baae36b231e16a3fdde9d8681deb4529b66c942984c2c7793877d13b1b,
https://www.praxikon.com/en/verkenner/definition/definitie-validatiedataset
(https://www.praxikon.com/api/v1/entities?id=praxikon%3Aeu%3Aai-act%3Adefinition%3Adefinitie-validatiedataset&effective_at=2026-08-08&known_at=2026-08-08&lang=en, accessed 2026-08-25)

Short form

praxikon:eu:ai-act:definition:definitie-validatiedataset@1.0.0 (sha256 b7e609ba)

BibTeX

@misc{praxikon-eu-ai-act-definition-definitie-validatiedataset-1-0-0,
  author       = {{Praxikon}},
  title        = {Validation data set},
  year         = {2026},
  version      = {1.0.0},
  number       = {praxikon:eu:ai-act:definition:definitie-validatiedataset},
  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 b7e609baae36b231e16a3fdde9d8681deb4529b66c942984c2c7793877d13b1b},
  url          = {https://www.praxikon.com/en/verkenner/definition/definitie-validatiedataset},
  urldate      = {2026-08-25},
  language     = {en}
}

CSL JSON

[
  {
    "id": "praxikon:eu:ai-act:definition:definitie-validatiedataset@1.0.0",
    "type": "dataset",
    "title": "Validation data set",
    "container-title": "AI Act Change & Evidence Graph",
    "publisher": "Praxikon",
    "version": "1.0.0",
    "number": "praxikon:eu:ai-act:definition:definitie-validatiedataset",
    "URL": "https://www.praxikon.com/en/verkenner/definition/definitie-validatiedataset",
    "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 b7e609baae36b231e16a3fdde9d8681deb4529b66c942984c2c7793877d13b1b; retrieved_from https://www.praxikon.com/api/v1/entities?id=praxikon%3Aeu%3Aai-act%3Adefinition%3Adefinitie-validatiedataset&effective_at=2026-08-08&known_at=2026-08-08&lang=en; licence https://www.praxikon.com/nl/legal/terms"
  }
]

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