Scale Dependent Data Duplication

Fuente: arXiv
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Hauptverfasser: Kazdan, Joshua, Levi, Noam, Schaeffer, Rylan, Chudnovsky, Jessica, Puri, Abhay, He, Bo, Donmez, Mehmet, Koyejo, Sanmi, Donoho, David
Format: Preprint
Veröffentlicht: 2026
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author Kazdan, Joshua
Levi, Noam
Schaeffer, Rylan
Chudnovsky, Jessica
Puri, Abhay
He, Bo
Donmez, Mehmet
Koyejo, Sanmi
Donoho, David
author_facet Kazdan, Joshua
Levi, Noam
Schaeffer, Rylan
Chudnovsky, Jessica
Puri, Abhay
He, Bo
Donmez, Mehmet
Koyejo, Sanmi
Donoho, David
contents Data duplication during pretraining can degrade generalization and lead to memorization, motivating aggressive deduplication pipelines. However, at web scale, it is unclear what constitutes a ``duplicate'': beyond surface-form matches, semantically equivalent documents (e.g. translations) may induce redundant training signals once models become sufficiently capable. Practically, this means that semantic duplicates operate increasingly like exact duplicates during training. We present evidence that duplication is scale-dependent in two ways. First, as model capability increases, cross-entropy loss gradients for semantically equivalent documents become more aligned. Smaller models, by contrast, produce gradients that reflect surface similarity (e.g., shared tokens) rather than semantic similarity. Second, we embedded all 192 million FineWeb-Edu-Dedup documents using EmbeddingGemma-300m. For moderate corpus sizes, the cosine similarity between nearest-neighbors follows an isotropic power law baseline. However, as corpus size grows to hundreds of billions of tokens, the nearest-neighbor similarities deviate sharply, indicating accelerated semantic collisions. Finally, controlled pretraining on data sampled with replacement from pools of finite unique documents shows that limited uniqueness yields mild degradation for small models, but rapidly increasing loss penalties for larger models, breaking naive scaling extrapolation. We derive explicit scaling laws that allow practitioners to estimate deviation from expected scaling due to limited semantic uniqueness of the pretraining corpus. Our results identify and resolve an unstudied source of scale-dependence, allowing for more accurate prediction at scale.
format Preprint
id arxiv_https___arxiv_org_abs_2603_06603
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Scale Dependent Data Duplication
Kazdan, Joshua
Levi, Noam
Schaeffer, Rylan
Chudnovsky, Jessica
Puri, Abhay
He, Bo
Donmez, Mehmet
Koyejo, Sanmi
Donoho, David
Machine Learning
Artificial Intelligence
Data duplication during pretraining can degrade generalization and lead to memorization, motivating aggressive deduplication pipelines. However, at web scale, it is unclear what constitutes a ``duplicate'': beyond surface-form matches, semantically equivalent documents (e.g. translations) may induce redundant training signals once models become sufficiently capable. Practically, this means that semantic duplicates operate increasingly like exact duplicates during training. We present evidence that duplication is scale-dependent in two ways. First, as model capability increases, cross-entropy loss gradients for semantically equivalent documents become more aligned. Smaller models, by contrast, produce gradients that reflect surface similarity (e.g., shared tokens) rather than semantic similarity. Second, we embedded all 192 million FineWeb-Edu-Dedup documents using EmbeddingGemma-300m. For moderate corpus sizes, the cosine similarity between nearest-neighbors follows an isotropic power law baseline. However, as corpus size grows to hundreds of billions of tokens, the nearest-neighbor similarities deviate sharply, indicating accelerated semantic collisions. Finally, controlled pretraining on data sampled with replacement from pools of finite unique documents shows that limited uniqueness yields mild degradation for small models, but rapidly increasing loss penalties for larger models, breaking naive scaling extrapolation. We derive explicit scaling laws that allow practitioners to estimate deviation from expected scaling due to limited semantic uniqueness of the pretraining corpus. Our results identify and resolve an unstudied source of scale-dependence, allowing for more accurate prediction at scale.
title Scale Dependent Data Duplication
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2603.06603