SCOPE: Stochastic and Counterbiased Option Placement for Evaluating Large Language Models

Fuente: arXiv
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Main Authors: Jeong, Wonjun, Kim, Dongseok, Whangbo, Taegkeun
Format: Preprint
Published: 2025
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author Jeong, Wonjun
Kim, Dongseok
Whangbo, Taegkeun
author_facet Jeong, Wonjun
Kim, Dongseok
Whangbo, Taegkeun
contents Large Language Models (LLMs) can achieve inflated scores on multiple-choice tasks by exploiting inherent biases in option positions or labels, rather than demonstrating genuine understanding. This study introduces SCOPE, an evaluation framework designed to measure and mitigate such selection bias in a dataset-independent manner. By repeatedly invoking a null prompt that lacks semantic content, SCOPE estimates each model's unique position-bias distribution. It then redistributes the answer slot according to the inverse-bias distribution, thereby equalizing the lucky-rate, the probability of selecting the correct answer by chance. Furthermore, it prevents semantically similar distractors from being placed adjacent to the answer, thereby blocking near-miss guesses based on superficial proximity cues. Across multiple benchmark experiments, SCOPE consistently outperformed existing debiasing methods in terms of stable performance improvements and showed clearer confidence distributions over correct options. This framework thus offers a new standard for enhancing the fairness and reliability of LLM evaluations.
format Preprint
id arxiv_https___arxiv_org_abs_2507_18182
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle SCOPE: Stochastic and Counterbiased Option Placement for Evaluating Large Language Models
Jeong, Wonjun
Kim, Dongseok
Whangbo, Taegkeun
Computation and Language
Artificial Intelligence
Large Language Models (LLMs) can achieve inflated scores on multiple-choice tasks by exploiting inherent biases in option positions or labels, rather than demonstrating genuine understanding. This study introduces SCOPE, an evaluation framework designed to measure and mitigate such selection bias in a dataset-independent manner. By repeatedly invoking a null prompt that lacks semantic content, SCOPE estimates each model's unique position-bias distribution. It then redistributes the answer slot according to the inverse-bias distribution, thereby equalizing the lucky-rate, the probability of selecting the correct answer by chance. Furthermore, it prevents semantically similar distractors from being placed adjacent to the answer, thereby blocking near-miss guesses based on superficial proximity cues. Across multiple benchmark experiments, SCOPE consistently outperformed existing debiasing methods in terms of stable performance improvements and showed clearer confidence distributions over correct options. This framework thus offers a new standard for enhancing the fairness and reliability of LLM evaluations.
title SCOPE: Stochastic and Counterbiased Option Placement for Evaluating Large Language Models
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2507.18182