Certified Error Control of Candidate Set Pruning for Two-Stage Relevance Ranking
Minghan Li, Xinyu Zhang, Ji Xin, Hongyang Zhang, Jimmy Lin · 2022
In information retrieval (IR), candidate set pruning has been commonly used to speed up twostage relevance ranking.However, such an approach lacks accurate error control and often trades accuracy against computational efficiency in an empirical fashion, missing theoretical guarantees.In this paper, we propose the concept of certified error control of candidate set pruning for relevance ranking, which means that the test error after pruning is guaranteed to be controlled under a user-specified threshold with high probability.Both in-domain and outof-domain experiments show that our method successfully prunes the first-stage retrieved candidate sets to improve the second-stage reranking speed while satisfying the pre-specified accuracy constraints in both settings.For example, on MS MARCO Passage v1, our method reduces the average candidate set size from 1000 to 27, increasing reranking speed by about 37 times, while keeping MRR@10 greater than a pre-specified value of 0.38 with about 90% empirical coverage.In contrast, empirical baselines fail to meet such requirements.