TFRank: Think-Free Reasoning Enables Practical Pointwise LLM Ranking

TL;DR

TFRank is an efficient pointwise reasoning ranker based on small-scale LLMs that integrates reasoning data and multi-task training to achieve high performance with reduced computational costs, enabling practical real-world applications.

Contribution

The paper introduces TFRank, a novel reasoning ranker that combines explicit reasoning with a think-free inference mode using small LLMs, reducing costs while maintaining high accuracy.

Findings

TFRank matches larger models' performance on BRIGHT benchmark.

It demonstrates strong competitiveness on the BEIR benchmark.

Achieves a balance between efficiency and ranking accuracy.

Abstract

Reasoning-intensive ranking models built on Large Language Models (LLMs) have made notable progress. However, existing approaches often rely on large-scale LLMs and explicit Chain-of-Thought (CoT) reasoning, resulting in high computational cost and latency that limit real-world use. To address this, we propose \textbf{TFRank}, an efficient pointwise reasoning ranker based on small-scale LLMs. To improve ranking performance, TFRank effectively integrates CoT data, fine-grained score supervision, and multi-task training. Furthermore, it achieves an efficient ``\textbf{T}hink-\textbf{F}ree" reasoning capability by employing a ``think-mode switch'' and pointwise format constraints. Specifically, this allows the model to leverage explicit reasoning during training while delivering precise relevance scores for complex queries at inference without generating any reasoning chains. Experiments show that TFRank achieves performance comparable to models with four times more parameters on the BRIGHT benchmark and demonstrates strong competitiveness on the BEIR benchmark. Further analysis shows that TFRank achieves an effective balance between performance and efficiency, providing a practical solution for integrating advanced reasoning into real-world systems. Our code and data are released in the repository: https://github.com/JOHNNY-fans/TFRank.