An Open Source Data Contamination Report for Large Language Models
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Abstract (arXiv)
Data contamination in model evaluation has become increasingly prevalent with the growing popularity of large language models. It allows models to "cheat" via memorisation instead of displaying true capabilities. Therefore, contamination analysis has become an crucial part of reliable model evaluation to validate results. However, existing contamination analysis is usually conducted internally by large language model developers and often lacks transparency and completeness. This paper presents an extensive data contamination report for over 15 popular large language models across six popular multiple-choice QA benchmarks. We also introduce an open-source pipeline that enables the community to perform contamination analysis on customised data and models. Our experiments reveal varying contamination levels ranging from 1% to 45% across benchmarks, with the contamination degree increasing rapidly over time. Performance analysis of large language models indicates that data contamination does not necessarily lead to increased model metrics: while significant accuracy boosts of up to 14% and 7% are observed on contaminated C-Eval and Hellaswag benchmarks, only a minimal increase is noted on contaminated MMLU. We also find larger models seem able to gain more advantages than smaller models on contaminated test sets.
Key facts. Cited by 51 papers in the map (data through 14 Oct 2026). Builds on 28 of its 57 references that are in the map. First posted on arXiv 26 Oct 2023.
Builds on
28 of 57 references.
References · 28
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- 2021Program Synthesis with Large Language Modelscited by 3,637
- 2017TriviaQA: A Large Scale Distantly Supervised Challenge Dataset for Reading Comprehensioncited by 2,955
- 2019PIQA: Reasoning about Physical Commonsense in Natural Languagecited by 2,883
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- 2023Stop Uploading Test Data in Plain Text: Practical Strategies for Mitigating Data Contamination by Evaluation Benchmarkscited by 142
- 2023Estimating Contamination via Perplexity: Quantifying Memorisation in Language Model Evaluationcited by 48
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- 2023FrameBERT: Conceptual Metaphor Detection with Frame Embedding Learningcited by 18
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- 2023RT-LM: Uncertainty-Aware Resource Management for Real-Time Inference of Language Modelscited by 11
- 2023Uncertainty-Aware Bootstrap Learning for Joint Extraction on Distantly-Supervised Datacited by 7
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- 2025Rethinking Evaluation in the Era of Time Series Foundation Models: (Un)known Information Leakage Challenges15 Oct 2025
- 2025Inflated Excellence or True Performance? Rethinking Medical Diagnostic Benchmarks with Dynamic Evaluation10 Oct 2025
- 2025Probing the Critical Point (CritPt) of AI Reasoning: a Frontier Physics Research Benchmark30 Sep 2025
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- 2025Answer-Centric or Reasoning-Driven? Uncovering the Latent Memory Anchor in LLMs21 Jun 2025
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- 2026Correcting test set contamination by spiking the training data24 May 2026
- 2026Provable Joint Decontamination for Benchmarking Multiple Large Language Models20 May 2026
- 2026LLM Benchmark Datasets Should Be Contamination-Resistant19 May 2026
- 2026Can Large Language Models Reliably Correct Errors in Low-Resource ASR? A Contamination-Aware Case Study on West Frisian19 May 2026
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