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      <title-group>
        <article-title>Overcoming Low-Utility Facets for Complex Answer Retrieval</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Sean MacAvaney</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Andrew Yates</string-name>
          <email>ayates@mpi-inf.mpg.de</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Arman Cohan</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Luca Soldaini</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Kai Hui</string-name>
          <email>kai.hui@sap.com</email>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Nazli Goharian</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Ophir Frieder</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>IRLab, Georgetown University</institution>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Max Planck Institute for Informatics</institution>
        </aff>
      </contrib-group>
      <fpage>46</fpage>
      <lpage>47</lpage>
      <abstract>
        <p>Complex Answer Retrieval (CAR) is the process of retrieval for questions whose answers require many details or additional context to explain thoroughly [2]. These questions can be formulated as having a topic entity and a facet. For instance, for the question \Is cheese healthy?", the topic is \Cheese" and the facet is \Health e ects". We observe that some facets, such as \Health e ects", exhibit low utility: answers to questions about the health e ects of cheese are unlikely to use the terms directly. Instead, they will include related entities, such as nutrients or related diseases. We call these low-utility facets because the terms in the facet are not used directly in the text, and thus the terms themselves do not provide much value. In contrast, high-utility facets use language that is speci c to the topic and can be found directly in relevant answers (e.g., a facet of \Curdling' for the question \Why does cheese curdle?"); it would be di cult (and unlikely) that an answer to this this question does not include the term \curdle" or \curdling". In this talk, we propose a two-pronged approach for CAR by modifying a leading neural information retrieval architecture (PACRR [3]).</p>
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