arXiv AI

Where Cross-Question Structure in LLM Errors Comes From: Shared Seeds, Shared Prompts, and Answer-Letter Preference

The study investigates why language models sometimes give consistent errors across related questions. By analyzing the correlation matrix of model responses, it finds that within a single model, independently drawn answers show no structure, but structure emerges when all questions share a random seed or few‑shot prompt. Across 24 models, the strongest additional structure is a preference for specific answer letters, especially in Llama‑3.2‑1B, and removing this effect leaves only a small excess of errors linked to a few model pairs.

arXiv AI
Oct 15

A, B, C, or Stable? Accuracy and Order Sensitivity Diverge in LLM Multiple-Choice Evaluation

The paper investigates whether accuracy and order sensitivity in large language model (LLM) multiple‑choice question (MCQ) evaluation move together. Using proprietary and open‑weight models on MMLU and ARC‑Challenge, the authors measure order sensitivity with flip rate and recall standard deviation (RStd) and find that these metrics often diverge from accuracy and from each other. They conclude that accuracy alone is insufficient and recommend reporting both flip rate and RStd alongside accuracy.

By Karl Hanna, Chen Feng
arXiv Computation and Language
Oct 28

Do We Need an LLM to Know Why Sources Conflict? Decision Models for Knowledge-Conflict Typing in RAG

The paper investigates whether fast, cost‑efficient decision models can classify the type of conflict among retrieved sources for a query, a task that improves response quality when the conflict type is known. Using the CONFLICTS benchmark, the authors evaluate 11 commercial decision models against Gemini LLMs, finding that most achieve 50–67% accuracy, often matching or surpassing Gemini 2.5 Flash while incurring 4–39× lower cost and 2.6–6.0× lower latency. A cascade approach that forwards uncertain cases to Gemini 3.8 Flash yields comparable performance at only 25–37% of its cost, and the resulting typed responses generally behave as expected when compared to LLM‑derived types.

By Parv Khatri, Harshul Jain, Mehak Kapoor, Tanya Sah
arXiv AI
Oct 12

The One-Word Census: Answer-Choice Conformity Across 105 Language Models

The study examines how 105 language models choose a single word from a large set of valid options, finding that 46% of the time they all pick the same word, "serendipity." Using 96 prompts that ask for one-word answers across various categories, the researchers measure convergence and each model’s share of the consensus. They observe that post‑training and persona‑tuned models diverge more, while heavily post‑trained assistants are more conformist, and that the field’s answer choices are more concentrated than human norms in most categories.

By Tapan Parikh
arXiv AI
Oct 2

Certainty Is Not Just Correctness: Rethinking Token-Level Certainty in LLM Reasoning

The paper investigates token‑level certainty as a proxy for correctness in large language models. It finds that certainty better predicts whether a model will answer a question correctly than it does whether a specific response is correct, and that certainty varies by token type and position. The authors show that using certainty early in generation to allocate responses and later to weight votes improves accuracy while dramatically cutting token cost.

By Yunfan Zhou, Ye Zhu, Zhihai Wang, Jianguo Yao, Haibing Guan, Xijun Li
arXiv Computation and Language
Oct 19

On the Position Bias of Large Language Models: A Comprehensive Study

The paper investigates position bias in large language models (LLMs) across a wide range of model sizes—from billions to trillions of parameters—and across five languages. It finds that while small-scale models and non‑English languages still exhibit noticeable position bias, larger models and the use of Chain‑of‑Thought prompting substantially reduce this bias. Additionally, the study shows that emerging thinking models with advanced reasoning capabilities are almost immune to position bias, indicating a promising but resource‑intensive path to mitigating this vulnerability.

By Yining Li, Huayang Li, Lemao Liu, Taro Watanabe
arXiv Computation and Language
Aug 25

Most of the LLM routing gap is task type

The paper investigates why large‑language‑model (LLM) routers—systems that select the best model for each query—often fail to outperform a single best model. By evaluating 14 models on 294 questions across seven task types and three languages, the authors find that a simple static mapping of task type to model improves 21 of the 29 questions that routing could potentially solve, and that learned routers do not significantly exceed this performance. The study highlights that most routing gains stem from task‑type specialization rather than complex learned decision rules.

By Janghoon Lee