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arXiv 提交日期: 2026-02-19
📄 Abstract - ABCD: All Biases Come Disguised

Multiple-choice question (MCQ) benchmarks have been a standard evaluation practice for measuring LLMs' ability to reason and answer knowledge-based questions. Through a synthetic NonsenseQA benchmark, we observe that different LLMs exhibit varying degrees of label-position-few-shot-prompt bias, where the model either uses the answer position, the label in front of the answer, the distributions of correct answers present in the few-shot prompt, or a combination of all to answer each MCQ question. We propose a simple bias-reduced evaluation protocol that replaces the labels of each question with uniform, unordered labels and prompts the LLM to use the whole answer presented. With a simple sentence similarity model, we demonstrate improved robustness and lower standard deviation between different permutations of answers with a minimal drop in LLM's performance, exposing the LLM's capabilities under reduced evaluation artifacts, without any help from the prompt examples or the option labels. Across multiple benchmarks and models, this protocol substantially improves the robustness to answer permutations, reducing mean accuracy variance $3\times$ with only a minimal decrease in the mean model's performance. Through ablation studies on various embedding models and similarity functions, we show that the method is more robust than the standard ones.

顶级标签: llm model evaluation benchmark
详细标签: multiple-choice evaluation position bias bias reduction robustness synthetic benchmark 或 搜索:

ABCD:所有偏见皆伪装而来 / ABCD: All Biases Come Disguised


1️⃣ 一句话总结

这篇论文发现大型语言模型在回答选择题时,会受到答案位置、选项标签和示例分布等表面线索的干扰,并提出了一种通过统一标签和答案整体匹配来减少评估偏差的简单方法,从而更真实地衡量模型的实际能力。

源自 arXiv: 2602.17445