REARANK: Reasoning Re-ranking Agent via Reinforcement Learning
Authors: name: Le Zhang, name: Bo Wang, name: Xipeng Qiu, name: Siva Reddy, name: Aishwarya Agrawal

We present REARANK, a large language model (LLM)-based listwise reasoning
reranking agent. REARANK explicitly reasons before reranking, significantly
improving both performance and interpretability. Leveraging reinforcement
learning and data augmentation, REARANK achieves substantial improvements over
baseline models across popular information retrieval benchmarks, notably
requiring only 179 annotated samples. Built on top of Qwen2.5-7B, our
REARANK-7B demonstrates performance comparable to GPT-4 on both in-domain and
out-of-domain benchmarks and even surpasses GPT-4 on reasoning-intensive BRIGHT
benchmarks. These results underscore the effectiveness of our approach and
highlight how reinforcement learning can enhance LLM reasoning capabilities in
reranking.