Open Domain Multi-document Summarization: A Comprehensive Study of Model Brittleness under Retrieval
Submission Type: Regular Long Paper
Submission Track: Summarization
Submission Track 2: Natural Language Generation
Keywords: summarization, multi-document summarization, retrieval, open-domain
TL;DR: We study a new, open-domain task definition for MDS where only a query is provided as input, and the relevant documents to summarize must be retrieved.
Abstract: Multi-document summarization (MDS) assumes a set of topic-related documents are provided as input. In practice, this document set is not always available; it would need to be retrieved given an information need, i.e. a question or topic statement, a setting we dub "open-domain" MDS. We study this more challenging setting by formalizing the task and bootstrapping it using existing datasets, retrievers and summarizers. Via extensive automatic and human evaluation, we determine: (1) state-of-the-art summarizers suffer large reductions in performance when applied to open-domain MDS, (2) additional training in the open-domain setting can reduce this sensitivity to imperfect retrieval, and (3) summarizers are insensitive to the retrieval of duplicate documents and the order of retrieved documents, but highly sensitive to other errors, like the retrieval of irrelevant documents. Based on our results, we provide practical guidelines to enable future work on open-domain MDS, e.g. how to choose the number of retrieved documents to summarize. Our results suggest that new retrieval and summarization methods and annotated resources for training and evaluation are necessary for further progress in the open-domain setting.
Submission Number: 4620
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