Can Query Expansion Improve Generalization of Strong Cross-Encoder Rankers?

Fuente: arXiv
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Main Authors: Li, Minghan, Zhuang, Honglei, Hui, Kai, Qin, Zhen, Lin, Jimmy, Jagerman, Rolf, Wang, Xuanhui, Bendersky, Michael
Format: Preprint
Published: 2023
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author Li, Minghan
Zhuang, Honglei
Hui, Kai
Qin, Zhen
Lin, Jimmy
Jagerman, Rolf
Wang, Xuanhui
Bendersky, Michael
author_facet Li, Minghan
Zhuang, Honglei
Hui, Kai
Qin, Zhen
Lin, Jimmy
Jagerman, Rolf
Wang, Xuanhui
Bendersky, Michael
contents Query expansion has been widely used to improve the search results of first-stage retrievers, yet its influence on second-stage, cross-encoder rankers remains under-explored. A recent work of Weller et al. [44] shows that current expansion techniques benefit weaker models such as DPR and BM25 but harm stronger rankers such as MonoT5. In this paper, we re-examine this conclusion and raise the following question: Can query expansion improve generalization of strong cross-encoder rankers? To answer this question, we first apply popular query expansion methods to state-of-the-art cross-encoder rankers and verify the deteriorated zero-shot performance. We identify two vital steps for cross-encoders in the experiment: high-quality keyword generation and minimal-disruptive query modification. We show that it is possible to improve the generalization of a strong neural ranker, by prompt engineering and aggregating the ranking results of each expanded query via fusion. Specifically, we first call an instruction-following language model to generate keywords through a reasoning chain. Leveraging self-consistency and reciprocal rank weighting, we further combine the ranking results of each expanded query dynamically. Experiments on BEIR and TREC Deep Learning 2019/2020 show that the nDCG@10 scores of both MonoT5 and RankT5 following these steps are improved, which points out a direction for applying query expansion to strong cross-encoder rankers.
format Preprint
id arxiv_https___arxiv_org_abs_2311_09175
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Can Query Expansion Improve Generalization of Strong Cross-Encoder Rankers?
Li, Minghan
Zhuang, Honglei
Hui, Kai
Qin, Zhen
Lin, Jimmy
Jagerman, Rolf
Wang, Xuanhui
Bendersky, Michael
Information Retrieval
Artificial Intelligence
Query expansion has been widely used to improve the search results of first-stage retrievers, yet its influence on second-stage, cross-encoder rankers remains under-explored. A recent work of Weller et al. [44] shows that current expansion techniques benefit weaker models such as DPR and BM25 but harm stronger rankers such as MonoT5. In this paper, we re-examine this conclusion and raise the following question: Can query expansion improve generalization of strong cross-encoder rankers? To answer this question, we first apply popular query expansion methods to state-of-the-art cross-encoder rankers and verify the deteriorated zero-shot performance. We identify two vital steps for cross-encoders in the experiment: high-quality keyword generation and minimal-disruptive query modification. We show that it is possible to improve the generalization of a strong neural ranker, by prompt engineering and aggregating the ranking results of each expanded query via fusion. Specifically, we first call an instruction-following language model to generate keywords through a reasoning chain. Leveraging self-consistency and reciprocal rank weighting, we further combine the ranking results of each expanded query dynamically. Experiments on BEIR and TREC Deep Learning 2019/2020 show that the nDCG@10 scores of both MonoT5 and RankT5 following these steps are improved, which points out a direction for applying query expansion to strong cross-encoder rankers.
title Can Query Expansion Improve Generalization of Strong Cross-Encoder Rankers?
topic Information Retrieval
Artificial Intelligence
url https://arxiv.org/abs/2311.09175