Unbiased Top-k Learning to Rank with Causal Likelihood Decomposition

Fuente: arXiv
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Autori principali: Zhao, Haiyuan, Xu, Jun, Zhang, Xiao, Cai, Guohao, Dong, Zhenhua, Wen, Ji-Rong
Natura: Preprint
Pubblicazione: 2022
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author Zhao, Haiyuan
Xu, Jun
Zhang, Xiao
Cai, Guohao
Dong, Zhenhua
Wen, Ji-Rong
author_facet Zhao, Haiyuan
Xu, Jun
Zhang, Xiao
Cai, Guohao
Dong, Zhenhua
Wen, Ji-Rong
contents Unbiased learning to rank has been proposed to alleviate the biases in the search ranking, making it possible to train ranking models with user interaction data. In real applications, search engines are designed to display only the most relevant k documents from the retrieved candidate set. The rest candidates are discarded. As a consequence, position bias and sample selection bias usually occur simultaneously. Existing unbiased learning to rank approaches either focus on one type of bias (e.g., position bias) or mitigate the position bias and sample selection bias with separate components, overlooking their associations. In this study, we first analyze the mechanisms and associations of position bias and sample selection bias from the viewpoint of a causal graph. Based on the analysis, we propose Causal Likelihood Decomposition (CLD), a unified approach to simultaneously mitigating these two biases in top-k learning to rank. By decomposing the log-likelihood of the biased data as an unbiased term that only related to relevance, plus other terms related to biases, CLD successfully detaches the relevance from position bias and sample selection bias. An unbiased ranking model can be obtained from the unbiased term, via maximizing the whole likelihood. An extension to the pairwise neural ranking is also developed. Advantages of CLD include theoretical soundness and a unified framework for pointwise and pairwise unbiased top-k learning to rank. Extensive experimental results verified that CLD, including its pairwise neural extension, outperformed the baselines by mitigating both the position bias and the sample selection bias. Empirical studies also showed that CLD is robust to the variation of bias severity and the click noise.
format Preprint
id arxiv_https___arxiv_org_abs_2204_00815
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle Unbiased Top-k Learning to Rank with Causal Likelihood Decomposition
Zhao, Haiyuan
Xu, Jun
Zhang, Xiao
Cai, Guohao
Dong, Zhenhua
Wen, Ji-Rong
Information Retrieval
Unbiased learning to rank has been proposed to alleviate the biases in the search ranking, making it possible to train ranking models with user interaction data. In real applications, search engines are designed to display only the most relevant k documents from the retrieved candidate set. The rest candidates are discarded. As a consequence, position bias and sample selection bias usually occur simultaneously. Existing unbiased learning to rank approaches either focus on one type of bias (e.g., position bias) or mitigate the position bias and sample selection bias with separate components, overlooking their associations. In this study, we first analyze the mechanisms and associations of position bias and sample selection bias from the viewpoint of a causal graph. Based on the analysis, we propose Causal Likelihood Decomposition (CLD), a unified approach to simultaneously mitigating these two biases in top-k learning to rank. By decomposing the log-likelihood of the biased data as an unbiased term that only related to relevance, plus other terms related to biases, CLD successfully detaches the relevance from position bias and sample selection bias. An unbiased ranking model can be obtained from the unbiased term, via maximizing the whole likelihood. An extension to the pairwise neural ranking is also developed. Advantages of CLD include theoretical soundness and a unified framework for pointwise and pairwise unbiased top-k learning to rank. Extensive experimental results verified that CLD, including its pairwise neural extension, outperformed the baselines by mitigating both the position bias and the sample selection bias. Empirical studies also showed that CLD is robust to the variation of bias severity and the click noise.
title Unbiased Top-k Learning to Rank with Causal Likelihood Decomposition
topic Information Retrieval
url https://arxiv.org/abs/2204.00815