Use of Multiple Documents as Evidence with Decreased Adding in a Japanese Question-answering System

Abstract

We propose a new method of using multiple documents as evidence with decreased adding to improve the performance of question-answering systems.Sometimes, the answer to a question may be found in multiple documents.In such cases, using multiple documents to predict answers may generate better answers than using a single document.Our method therefore uses information from multiple documents, adding the scores of candidate answers extracted from various documents.However, because simply adding the scores can degrade the performance of question-answering systems, we add the scores with progressively decreasing weights to reduce the negative effect of simple adding.We carried out experiments using the Question-Answering Challenge (QAC) test collection.The results showed that our method produced a statistically significant improvement, with the degree of improvement ranging fro 0.05 to 0.14.These results, and the fact that our method is simple and easy to use, indicate its potential feasibility and utility in question-answering systems.Experiments comparing our decreased adding method with several previously proposed methods that use multiple documents showed that our method was more effective than these other methods.