Multi-hop Reading Comprehension through Question Decomposition and Rescoring
Sewon Min, Victor W. Zhong, Luke Zettlemoyer, Hannaneh Hajishirzi · 2019
Multi-hop Reading Comprehension (RC) requires reasoning and aggregation across several paragraphs.We propose a system for multi-hop RC that decomposes a compositional question into simpler sub-questions that can be answered by off-the-shelf single-hop RC models.Since annotations for such decomposition are expensive, we recast subquestion generation as a span prediction problem and show that our method, trained using only 400 labeled examples, generates sub-questions that are as effective as humanauthored sub-questions.We also introduce a new global rescoring approach that considers each decomposition (i.e. the sub-questions and their answers) to select the best final answer, greatly improving overall performance.Our experiments on HOTPOTQA show that this approach achieves the state-of-the-art results, while providing explainable evidence for its decision making in the form of sub-questions.