Summa is a hierarchical summarization system. Summa produces a hierarchy of relatively short summaries, where the top level provides a general overview and users can navigate the hierarchy to drill down for more details on topics of interest. Summa optimizes for coherence as well as coverage of salient information. In an Amazon Mechanical Turk evaluation, users prefer Summa ten times as often as flat MDS and three times as often as timelines. Summa was developed at the University of Washington's Turing Center.


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  • Hierarchical Summarization: Scaling Up Multi-Document Summarization
    Janara Christensen, Stephen Soderland, Gagan Bansal, and Mausam
    Proceedings of the 52nd Annual Meeting of the Association for Computational Linguistics (ACL 2014)
  • Towards Coherent Multi-Document Summarization
    Janara Christensen, Mausam, Stephen Soderland, and Oren Etzioni
    Proceedings of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (NAACL 2013)
    pdf | bibtex