RADAR: Mechanistic Pathways for Detecting Data Contamination in LLM Evaluation

Fuente: arXiv
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Main Authors: Kattamuri, Ashish, Fartale, Harshwardhan, Vats, Arpita, Raja, Rahul, Prasad, Ishita
Format: Preprint
Published: 2025
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author Kattamuri, Ashish
Fartale, Harshwardhan
Vats, Arpita
Raja, Rahul
Prasad, Ishita
author_facet Kattamuri, Ashish
Fartale, Harshwardhan
Vats, Arpita
Raja, Rahul
Prasad, Ishita
contents Data contamination poses a significant challenge to reliable LLM evaluation, where models may achieve high performance by memorizing training data rather than demonstrating genuine reasoning capabilities. We introduce RADAR (Recall vs. Reasoning Detection through Activation Representation), a novel framework that leverages mechanistic interpretability to detect contamination by distinguishing recall-based from reasoning-based model responses. RADAR extracts 37 features spanning surface-level confidence trajectories and deep mechanistic properties including attention specialization, circuit dynamics, and activation flow patterns. Using an ensemble of classifiers trained on these features, RADAR achieves 93\% accuracy on a diverse evaluation set, with perfect performance on clear cases and 76.7\% accuracy on challenging ambiguous examples. This work demonstrates the potential of mechanistic interpretability for advancing LLM evaluation beyond traditional surface-level metrics.
format Preprint
id arxiv_https___arxiv_org_abs_2510_08931
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle RADAR: Mechanistic Pathways for Detecting Data Contamination in LLM Evaluation
Kattamuri, Ashish
Fartale, Harshwardhan
Vats, Arpita
Raja, Rahul
Prasad, Ishita
Artificial Intelligence
Machine Learning
Data contamination poses a significant challenge to reliable LLM evaluation, where models may achieve high performance by memorizing training data rather than demonstrating genuine reasoning capabilities. We introduce RADAR (Recall vs. Reasoning Detection through Activation Representation), a novel framework that leverages mechanistic interpretability to detect contamination by distinguishing recall-based from reasoning-based model responses. RADAR extracts 37 features spanning surface-level confidence trajectories and deep mechanistic properties including attention specialization, circuit dynamics, and activation flow patterns. Using an ensemble of classifiers trained on these features, RADAR achieves 93\% accuracy on a diverse evaluation set, with perfect performance on clear cases and 76.7\% accuracy on challenging ambiguous examples. This work demonstrates the potential of mechanistic interpretability for advancing LLM evaluation beyond traditional surface-level metrics.
title RADAR: Mechanistic Pathways for Detecting Data Contamination in LLM Evaluation
topic Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2510.08931