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<Paper uid="E06-3005">
  <Title>Developing an approach for why-question answering</Title>
  <Section position="5" start_page="44" end_page="45" type="concl">
    <SectionTitle>
4 Conclusions and further research
</SectionTitle>
    <Paragraph position="0"> We created a data collection for research into why-questions and for development of a method for why-QA. The collection comprises a sufficient amount of why-questions. For each question, the source document and one or two user-formulated answers are available in the data set. The resulting data set is of importance for our research as well as other research in the field of why-QA.</Paragraph>
    <Paragraph position="1"> We developed a question analysis method for why-questions, based on syntactic categorization and answer type determination. In-depth evaluation of this module will be performed in a later stage, when the other parts of our QA approach have been developed, and a test set has been collected. We believe that the first test results, which show a high precision and low recall, are promising for future development of our method for why-QA.</Paragraph>
    <Paragraph position="2"> We think that, just as for factoid-QA, answer type determination can play an important role in question analysis for why-questions. Therefore, Kupiec' suggestion that conventional question analysis techniques are not suitable for why-QA can be made more precise by saying that these methods may be useful for a (potentially small) subset of why-questions. The issue of recall, both for human and machine processing, needs further analysis.</Paragraph>
    <Paragraph position="3"> In the near future, our work will focus on development of the next part of our approach for why-QA.</Paragraph>
    <Paragraph position="4"> Until now we have focused on the first of four sub-tasks in QA, viz. (1) question analysis (2) retrieval of candidate paragraphs; (3) paragraph analysis and selection; and (4) answer generation. Of the remaining three sub-tasks, we will focus on paragraph analysis (3). In order to clarify the relevance of the paragraph analysis step, let us briefly discuss the QA-processes that follows question analysis.</Paragraph>
    <Paragraph position="5"> The retrieval module, which comes directly after the question analysis module, uses the output of the question analysis module for finding candidate answer paragraphs (or documents). Paragraph retrieval can be straightforward: in existing approaches for factoid-QA, candidate paragraphs are selected based on keyword matching only. For the current research, we do not aim at creating our own paragraph selection technique.</Paragraph>
    <Paragraph position="6"> More interesting than paragraph retrieval is the next step of QA: paragraph analysis. The paragraph analysis module tries to determine whether the candidate paragraphs contain potential answers. In case of who-questions, noun phrases denoting persons are potential  answers; in case of why-questions, reasons are potential answers. In the paragraph analysis stage, our answer sub-types come into play. The question analysis module determines the answer type for the input question, which is motivation, cause, purpose, or circumstance. The paragraph analysis module uses this information for searching candidate answers in a paragraph. As has been said before, the procedure for assigning the correct sub-type needs further investigation in order to increase the coverage and the contribution that answer sub-type classification can make to the performance of why-question answering.</Paragraph>
    <Paragraph position="7"> Once the system has extracted potential answers from one or more paragraphs with the same topic as the question, the eventual answer has to be delimited and reformulated if necessary.</Paragraph>
  </Section>
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