Exact phrases in information retrieval for question answering
Svetlana Stoyanchev, Young Chol Song, William Lahti · 2008
Question answering (QA) is the task of finding a concise answer to a natural language question. The first stage of QA involves information retrieval. Therefore, performance of an information retrieval subsystem serves as an upper bound for the performance of a QA system. In this work we use phrases automatically identified from questions as exact match constituents to search queries. Our results show an improvement over baseline on several document and sentence retrieval measures on the WEB dataset. We get a 20% relative improvement in MRR for sentence extraction on the WEB dataset when using automatically generated phrases and a further 9.5% relative improvement when using manually annotated phrases. Surprisingly, a separate experiment on the indexed AQUAINT dataset showed no effect on IR performance of using exact phrases.