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Main Authors: Lunardi, Riccardo, Della Mea, Vincenzo, Mizzaro, Stefano, Roitero, Kevin
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2509.04013
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author Lunardi, Riccardo
Della Mea, Vincenzo
Mizzaro, Stefano
Roitero, Kevin
author_facet Lunardi, Riccardo
Della Mea, Vincenzo
Mizzaro, Stefano
Roitero, Kevin
contents Large Language Models (LLMs) effectiveness is usually evaluated by means of benchmarks such as MMLU, ARC-C, or HellaSwag, where questions are presented in their original wording, thus in a fixed, standardized format. However, real-world applications involve linguistic variability, requiring models to maintain their effectiveness across diverse rewordings of the same question or query. In this study, we systematically assess the robustness of LLMs to paraphrased benchmark questions and investigate whether benchmark-based evaluations provide a reliable measure of model capabilities. We systematically generate various paraphrases of all the questions across six different common benchmarks, and measure the resulting variations in effectiveness of 34 state-of-the-art LLMs, of different size and effectiveness. Our findings reveal that while LLM rankings remain relatively stable across paraphrased inputs, absolute effectiveness scores change, and decline significantly. This suggests that LLMs struggle with linguistic variability, raising concerns about their generalization abilities and evaluation methodologies. Furthermore, the observed performance drop challenges the reliability of benchmark-based evaluations, indicating that high benchmark scores may not fully capture a model's robustness to real-world input variations. We discuss the implications of these findings for LLM evaluation methodologies, emphasizing the need for robustness-aware benchmarks that better reflect practical deployment scenarios.
format Preprint
id arxiv_https___arxiv_org_abs_2509_04013
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On Robustness and Reliability of Benchmark-Based Evaluation of LLMs
Lunardi, Riccardo
Della Mea, Vincenzo
Mizzaro, Stefano
Roitero, Kevin
Computation and Language
Artificial Intelligence
Large Language Models (LLMs) effectiveness is usually evaluated by means of benchmarks such as MMLU, ARC-C, or HellaSwag, where questions are presented in their original wording, thus in a fixed, standardized format. However, real-world applications involve linguistic variability, requiring models to maintain their effectiveness across diverse rewordings of the same question or query. In this study, we systematically assess the robustness of LLMs to paraphrased benchmark questions and investigate whether benchmark-based evaluations provide a reliable measure of model capabilities. We systematically generate various paraphrases of all the questions across six different common benchmarks, and measure the resulting variations in effectiveness of 34 state-of-the-art LLMs, of different size and effectiveness. Our findings reveal that while LLM rankings remain relatively stable across paraphrased inputs, absolute effectiveness scores change, and decline significantly. This suggests that LLMs struggle with linguistic variability, raising concerns about their generalization abilities and evaluation methodologies. Furthermore, the observed performance drop challenges the reliability of benchmark-based evaluations, indicating that high benchmark scores may not fully capture a model's robustness to real-world input variations. We discuss the implications of these findings for LLM evaluation methodologies, emphasizing the need for robustness-aware benchmarks that better reflect practical deployment scenarios.
title On Robustness and Reliability of Benchmark-Based Evaluation of LLMs
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2509.04013