Elo-Evolve: A Co-evolutionary Framework for Language Model Alignment

Fuente: arXiv
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Main Authors: Zhao, Jing, Zhen, Ting, Bao, Junwei, Jiang, Hongfei, Song, Yang
Format: Preprint
Published: 2026
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author Zhao, Jing
Zhen, Ting
Bao, Junwei
Jiang, Hongfei
Song, Yang
author_facet Zhao, Jing
Zhen, Ting
Bao, Junwei
Jiang, Hongfei
Song, Yang
contents Current alignment methods for Large Language Models (LLMs) rely on compressing vast amounts of human preference data into static, absolute reward functions, leading to data scarcity, noise sensitivity, and training instability. We introduce Elo-Evolve, a co-evolutionary framework that redefines alignment as dynamic multi-agent competition within an adaptive opponent pool. Our approach makes two key innovations: (1) eliminating Bradley-Terry model dependencies by learning directly from binary win/loss outcomes in pairwise competitions, and (2) implementing Elo-orchestrated opponent selection that provides automatic curriculum learning through temperature-controlled sampling. We ground our approach in PAC learning theory, demonstrating that pairwise comparison achieves superior sample complexity and empirically validate a 4.5x noise reduction compared to absolute scoring approaches. Experimentally, we train a Qwen2.5-7B model using our framework with opponents including Qwen2.5-14B, Qwen2.5-32B, and Qwen3-8B models. Results demonstrate a clear performance hierarchy: point-based methods < static pairwise training < Elo-Evolve across Alpaca Eval 2.0 and MT-Bench, validating the progressive benefits of pairwise comparison and dynamic opponent selection for LLM alignment.
format Preprint
id arxiv_https___arxiv_org_abs_2602_13575
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Elo-Evolve: A Co-evolutionary Framework for Language Model Alignment
Zhao, Jing
Zhen, Ting
Bao, Junwei
Jiang, Hongfei
Song, Yang
Computation and Language
Artificial Intelligence
Current alignment methods for Large Language Models (LLMs) rely on compressing vast amounts of human preference data into static, absolute reward functions, leading to data scarcity, noise sensitivity, and training instability. We introduce Elo-Evolve, a co-evolutionary framework that redefines alignment as dynamic multi-agent competition within an adaptive opponent pool. Our approach makes two key innovations: (1) eliminating Bradley-Terry model dependencies by learning directly from binary win/loss outcomes in pairwise competitions, and (2) implementing Elo-orchestrated opponent selection that provides automatic curriculum learning through temperature-controlled sampling. We ground our approach in PAC learning theory, demonstrating that pairwise comparison achieves superior sample complexity and empirically validate a 4.5x noise reduction compared to absolute scoring approaches. Experimentally, we train a Qwen2.5-7B model using our framework with opponents including Qwen2.5-14B, Qwen2.5-32B, and Qwen3-8B models. Results demonstrate a clear performance hierarchy: point-based methods < static pairwise training < Elo-Evolve across Alpaca Eval 2.0 and MT-Bench, validating the progressive benefits of pairwise comparison and dynamic opponent selection for LLM alignment.
title Elo-Evolve: A Co-evolutionary Framework for Language Model Alignment
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2602.13575