Augmented Relevance Datasets with Fine-Tuned Small LLMs
Quentin Fitte-Rey, Matyas Amrouche, Romain Deveaud
TL;DR
The paper tackles the high cost and reproducibility concerns of human relevance labeling by employing small open-source LLMs (7–9B) that are fine-tuned with a carefully curated set of relevance examples. A structured prompting framework and LoRA-based fine-tuning align these models with human judgments, enabling them to augment training data for dense re-ranking while reducing reliance on closed APIs. Results show that fine-tuned small LLMs can surpass vanilla baselines and achieve competitive ranking performance, with Gemma 2 9B delivering the strongest relative-order alignment (tau ≈ 0.71) and improving NDCG/MRR on downstream tasks. The work demonstrates a scalable, reproducible path for dataset augmentation in IR, offering practical benefits for production search pipelines and mitigating risks associated with API-dependent models.
Abstract
Building high-quality datasets and labeling query-document relevance are essential yet resource-intensive tasks, requiring detailed guidelines and substantial effort from human annotators. This paper explores the use of small, fine-tuned large language models (LLMs) to automate relevance assessment, with a focus on improving ranking models' performance by augmenting their training dataset. We fine-tuned small LLMs to enhance relevance assessments, thereby improving dataset creation quality for downstream ranking model training. Our experiments demonstrate that these fine-tuned small LLMs not only outperform certain closed source models on our dataset but also lead to substantial improvements in ranking model performance. These results highlight the potential of leveraging small LLMs for efficient and scalable dataset augmentation, providing a practical solution for search engine optimization.
