Using syntactic information for improving why-question answering

Abstract

In this paper, we extend an existing paragraph retrieval approach to why-question answering. The starting-point is a system that retrieves a relevant answer for 73% of the test questions. However, in 41% of these cases, the highest ranked relevant answer is not ranked in the top-10. We aim to improve the ranking by adding a re-ranking module. For re-ranking we consider 31 features pertaining to the syntactic structure of the question and the candidate answer. We find a significant improvement over the baseline for both success@10 and MRR@150. The most important features for re-ranking are the baseline score, the presence of cue words, the question's main verb, and the relation between question focus and document title. © Suzan Verberne, 2008.