Inter-Passage Verification for Multi-evidence Multi-answer QA

Multi-answer question answering (QA), where questions can have many valid answers, presents a significant challenge for existing retrieval-augmented generation-based QA systems, as these systems struggle to retrieve and then synthesize a large number of evidence passages.To tackle these challenges, we propose a new multi-answer QA framework -Retrievalaugmented Independent Reading with Interpassage Verification (RI 2 VER).Our framework retrieves a large set of passages and processes each passage individually to generate an initial high-recall but noisy answer set.Then we propose a new inter-passage verification pipeline that validates every candidate answer through (1) Verification Question Generation, (2) Gathering Additional Evidence, and (3) Verification with inter-passage synthesis.Evaluations on the QAMPARI and RoMQA datasets demonstrate that our framework significantly outperforms existing baselines across various model sizes, achieving an average F1 score improvement of 11.17%.Further analysis validates that our inter-passage verification pipeline enables our framework to be particularly beneficial for questions requiring multievidence synthesis. 1