A field guide to AI positions

Overfitting

Inside a model.

Publication dates and source age

Sources counted: 1

Publication dates are unavailable.

Assessed at this edition's evidence cutoff: 2026-09-15. 18-month boundary: 2025-03-15.

Some publication dates are unknown; the newest dated source may not be the newest source overall.

Publication age does not tell us whether a claim is still valid. Reading an old source again does not make its publication date newer. An update date does not establish that the passage we used was updated.

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Prepared with AI assistance. Not independently fact-checked. Original sources and qualifications are below.

In plain language

When a model fits its training examples so closely that it performs worse on new examples. [1]

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Explanation based on the linked sources. Claim ID: claim-term-overfitting-1a5192ba3d7825ca26b24a72. Edition 0.20.0.

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Limits & distinctions

A good training score alone does not show useful performance elsewhere. Underfitting is different: the model already struggles with its training examples. [1]

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Explanation based on the linked sources. Claim ID: claim-term-overfitting-09422ce4d5c74cb753a9bb98. Edition 0.20.0.

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A fuller explanation

Training can fit details that do not carry over to new data. A warning sign is training error falling while error on separate validation data rises. [1]

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Explanation based on the linked sources. Claim ID: claim-term-overfitting-1e4c26398ee834b2e16dc7b8. Edition 0.20.0.

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How it relates to the map

Look for results on separate, relevant examples when assessing claims about model quality. [1]

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Editorial interpretation or qualification. Claim ID: claim-term-overfitting-25f52a21ad9f2e54a62ed1b2. Edition 0.20.0.

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https://theaiatlas.org/ideas/overfitting/

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Sources and what we read

  1. 1. Overfitting

    Google for Developers · First-hand source · Published date unavailable · Updated 2025-12-03 · Material last read 2026-09-15

    Publication dates and source age

    Sources counted: 1

    Publication dates are unavailable.

    Assessed at this edition's evidence cutoff: 2026-09-15. 18-month boundary: 2025-03-15.

    Some publication dates are unknown; the newest dated source may not be the newest source overall.

    Publication age does not tell us whether a claim is still valid. Reading an old source again does not make its publication date newer. An update date does not establish that the passage we used was updated.

    Read scope is described in the source note.

    No archive check recorded.

    Read training versus new-data performance, the underfitting comparison and generalization curves. Illustrative curves are not evidence about a particular model.

    Source ID: glossary-model-overfitting

Edition and machine-readable evidence

Content version 0.20.0. Evidence cutoff 2026-09-15; this does not mean every source was read on that day.

Pinned complete dataset · Complete evidence page · Agent consumption guide