Augmenting Pre-trained Language Models with QA-Memory for Open-Domain Question Answering

Wenhu Chen, Pat Verga, Michiel de Jong, John Wieting, William W. Cohen


Abstract
Existing state-of-the-art methods for open-domain question-answering (ODQA) use an open book approach in which information is first retrieved from a large text corpus or knowledge base (KB) and then reasoned over to produce an answer. A recent alternative is to retrieve from a collection of previously-generated question-answer pairs; this has several practical advantages including being more memory and compute-efficient. Question-answer pairs are also appealing in that they can be viewed as an intermediate between text and KB triples: like KB triples, they often concisely express a single relationship, but like text, have much higher coverage than traditional KBs. In this work, we describe a new QA system that augments a text-to-text model with a large memory of question-answer pairs, and a new pre-training task for the latent step of question retrieval. The pre-training task substantially simplifies training and greatly improves performance on smaller QA benchmarks. Unlike prior systems of this sort, our QA system can also answer multi-hop questions that do not explicitly appear in the collection of stored question-answer pairs.
Anthology ID:
2023.eacl-main.117
Volume:
Proceedings of the 17th Conference of the European Chapter of the Association for Computational Linguistics
Month:
May
Year:
2023
Address:
Dubrovnik, Croatia
Editors:
Andreas Vlachos, Isabelle Augenstein
Venue:
EACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1597–1610
Language:
URL:
https://aclanthology.org/2023.eacl-main.117
DOI:
10.18653/v1/2023.eacl-main.117
Bibkey:
Cite (ACL):
Wenhu Chen, Pat Verga, Michiel de Jong, John Wieting, and William W. Cohen. 2023. Augmenting Pre-trained Language Models with QA-Memory for Open-Domain Question Answering. In Proceedings of the 17th Conference of the European Chapter of the Association for Computational Linguistics, pages 1597–1610, Dubrovnik, Croatia. Association for Computational Linguistics.
Cite (Informal):
Augmenting Pre-trained Language Models with QA-Memory for Open-Domain Question Answering (Chen et al., EACL 2023)
Copy Citation:
PDF:
https://aclanthology.org/2023.eacl-main.117.pdf
Video:
 https://aclanthology.org/2023.eacl-main.117.mp4