Grape: Knowledge Graph Enhanced Passage Reader for Open-domain Question Answering

A common thread of open-domain question answering (QA) models employs a retrieverreader pipeline that first retrieves a handful of relevant passages from Wikipedia and then peruses the passages to produce an answer. However, even state-of-the-art readers fail to capture the complex relationships between entities appearing in questions and retrieved passages, leading to answers that contradict the facts. In light of this, we propose a novel knowledge Graph enhanced passage reader, namely GRAPE , to improve the reader performance for open-domain QA. Specifically, for each pair of question and retrieved passage, we first construct a localized bipartite graph, attributed to entity embeddings extracted from the intermediate layer of the reader model. Then, a graph neural network learns relational knowledge while fusing graph and contextual representations into the hidden states of the reader model. Experiments on three open-domain QA benchmarks show GRAPE can improve the state-of-the-art performance by up to 2.2 exact match score with a negligible overhead increase, with the same retriever and retrieved passages. Our code is publicly available at https://github.com/jumxglhf/GRAPE.

Question: What is the primary language of China? Retrieved Wikipedia passage (ID: 253645): Language of the People's Republic of China and of the Republic of China (Taiwan), and one of the official languages of Singapore. Standard Mandarin Chinese now dominates public life in mainland China. Outside China and Taiwan, the only varieties of Chinese commonly taught in university courses are Mandarin and Cantonese. Answer (SoTA reader): Cantonese Answer (ours): Standard Mandarin Factual Triplet from Wikidata: Question: What does the Missouri river bisect? Retrieved Wikipedia passage (ID: 19591): The Missouri River is the longest river in North America. Rising in the Rocky Mountains of western Montana the Missouri flows east and south for before entering the Mississippi River north of St. Louis, Missouri. The river drains a sparsely populated, … 500,000 square miles, which includes parts of ten U.S. States and two Canadian provinces. Answer (SoTA reader): Missouri Answer (ours): Mississippi River Factual Triplet from Wikidata: