arXiv Computation and Language

SynthSentry: Detecting Synthetic Data Contamination in Language Model Training Data

The paper introduces SynthSentry, a model‑agnostic method for detecting synthetic data contamination in language‑model training corpora. It computes a distributional divergence score based on lexical diversity collapse, n‑gram tail truncation, and perplexity variance across reference models, requiring no access to the generating model or synthetic labels. Experiments on English corpora contaminated by small open‑weight generators and an instruction‑tuned model show that SynthSentry ranks contamination severity accurately, maintains low false‑positive rates after calibration, and does not degrade downstream fine‑tuning performance at the tested scale.

arXiv AI
Oct 9

Obscuring Data Contamination Through Translation: Evidence from Arabic Corpora

The study investigates how exposing large language models to Arabic translations of English benchmark tasks can hide data contamination from standard English-only detection methods. By testing four instruction-tuned models with increasing Arabic exposure, the authors find that traditional probes like TS-Guessing and Min-K%++ fail to detect contamination, yet English performance still improves. They propose a new Translation-Aware Contamination Detection (TACD) method that uses cross-lingual consistency and choice reordering to reveal contamination effects that are otherwise invisible to English-only diagnostics.

By Chaymaa Abbas, Nour Shammaa, Mariette Awad
arXiv AI
Jun 17

Combating Data Laundering in LLM Training

arXiv:2604. 01904v3 Announce Type: replace-cross Abstract: Post-hoc unauthorized-training data detection for large language models (LLMs) typically assumes a query-with-originals regime: rights holders query a target LLM with raw proprietary data and assess whether the model assigns them stronger memorization-based detection signals, e.

By Muxing Li, Zesheng Ye, Sharon Li, Feng Liu
arXiv Computation and Language
Sep 4

Contamination Inflates Scores but Rarely Reorders Large Language Model Leaderboards

The paper investigates how benchmark contamination—leakage of test items into training data—affects large language model (LLM) leaderboards. By comparing original test items with semantically equivalent paraphrases, the authors measure contamination as a violation of anchor-item invariance and find that it inflates absolute scores but rarely changes model rankings. Across 47 public models and 74 finetuned models on four benchmarks, the rank correlation between standard and paraphrase-controlled leaderboards is 0.997, with only a handful of cases showing differential contamination that could alter rankings.

By Xingyao Xiao (Stanford University), Yihong Cheng (City University of Macau)
arXiv AI
Oct 9

Large Language Model Turnover Undermines Screening for Artificial Intelligence-Assisted Scientific Writing

The study examines how the rapid turnover of large language models (LLMs) undermines the effectiveness of AI‑detectors used to screen scientific manuscripts. By comparing 4,000 PNAS abstracts rewritten by 23 different LLM versions released between June 2023 and August 2026, the authors show that detectors trained on past versions can fail dramatically at generation boundaries, missing up to 96% of rewrites just after a sharp transition. Even detectors updated to newer versions can overlook rewrites of older models, and a commercial detector missed most rewrites of the newest version while flagging few human‑written abstracts.

By Kazuki Nakajima, Takayuki Mizuno
arXiv Machine Learning
Jul 30

RAGuard: A Layered Defense Framework for Retrieval-Augmented Generation Systems Against Data Poisoning

arXiv:2607. 26339v1 Announce Type: new Abstract: Retrieval-Augmented Generation (RAG) systems ground large language models (LLMs) in external corpora, but this reliance exposes them to corpus poisoning: maliciously injected passages that manipulate retrieved evidence.

By Pushkal Kumar, Tucker Nielson, Tanish Kolhe, Shubham Zala, Vincent Li
Hugging Face Trending Papers
Aug 17

Toward Better Assessment of LLMs' Performance in Clinical Error Detection

Automated detection of errors in clinical documentation is a promising application of large language models (LLMs), yet decisions to deploy such models rest on benchmarks that evaluate each clinical note in isolation. Error-detection benchmarks are typically constructed by injecting errors into notes, such that each erroneous note has a natural counterpart.

arXiv Machine Learning
Aug 11

UNMASK: Discovering and Causally Verifying Spurious Shortcuts in Text Classifiers

arXiv:2608. 09209v1 Announce Type: cross Abstract: Neural language models trained on large crowdsourced corpora frequently exploit spurious surface patterns tied to target labels without true linguistic or causal relevance, boosting benchmark performance while failing on adversarial or out-of-distribution inputs.

By Chidaksh Ravuru, Shashank Srivastava
arXiv AI
Oct 28

Follow the Gradient: Tracing Safety Degradation Back to Training Data

The paper introduces SimpleLoRIF, a scalable gradient‑embedding technique that pinpoints fine‑tuning examples whose gradients align with unsafe behavior in large language models. By applying this method, the authors create SafeTulu, a version of Tulu 3 with the 20 % of most unsafe‑aligned examples removed, which reduces GCG attack success by up to 22 % across several LLMs while largely preserving or improving capability. The study also highlights previously under‑studied safety‑degrading data sources such as tool‑execution failures and narrative arithmetic.

By Saket Reddy, Amro Abbas, Anshuman Suri, Ari Morcos, David Schwab, Pratyush Maini
arXiv Machine Learning
Oct 3

Source Identification Is Not Fitness Testing: Measuring the Limits of Synthetic-Data Attribution

The study investigates whether provenance information can reliably identify the source of synthetic text and whether this identification improves the selection of training data. Using financial‑risk text, the authors achieve 98.7% accuracy in attributing original generated passages, but accuracy drops to 53.1% after paraphrasing and 29.0% after style rewriting. They compare two selection strategies—one based on source provenance and another on a reference model score—across three rounds of generation and retraining, finding that the two methods choose different examples but do not produce a consistent difference in model degradation. The results suggest that source attribution and useful data selection are distinct challenges, and neither provenance nor the tested proxy suffices to guarantee stable recursive training behavior.

By Joss Armstrong