Fine-Tuning BERT for COVID-19 Domain Ad-Hoc IR by Using Pseudo-qrels

This work analyzes the feasibility of training a neural retrieval system for a collection of scientific papers about COVID-19 using pseudo-qrels extracted from the collection. We propose a method for generating pseudo-qrels that exploits two characteristics present in scientific articles: a) the relationship between title and abstract, and b) the relationship between articles through sentences containing citations. Through these signals we generate pseudo-queries and their respective pseudo-positive (relevant documents) and pseudo-negative (non-relevant documents) examples. The article retrieval process combines a ranking model based on term-maching techniques and a neural one based on pretrained BERT models. BERT models are fine-tuned to the task using the pseudo-qrels generated. We compare different BERT models, both open domain and biomedical domain, and also the generated pseudo-qrels with the open domain MS-Marco dataset for fine-tuning the models. The results obtained on the TREC-COVID collection show that pseudo-qrels provide a significant improvement to neural models, both against classic IR baselines based on term-matching and neural systems trained on MS-Marco.