What is the extractive technique used for summarization?
Answer with content missing: (baseline list) TextRank, KLSum, Lead-1, Lead-K and Random-K
Unilateral contracts, such as terms of service, play a substantial role in modern digital life. However, few users read these documents before accepting the terms within, as they are too long and the language too complicated. We propose the task of summarizing such legal documents in plain English, which would enable users to have a better understanding of the terms they are accepting. We propose an initial dataset of legal text snippets paired with summaries written in plain English. We verify the quality of these summaries manually and show that they involve heavy abstraction, compression, and simplification. Initial experiments show that unsupervised extractive summarization methods do not perform well on this task due to the level of abstraction and style differences. We conclude with a call for resource and technique development for simplification and style transfer for legal language.
Although internet users accept unilateral contracts such as terms of service on a regular basis, it is well known that these users rarely read them. Nonetheless, these are binding contractual agreements. A recent study suggests that up to 98% of users do not fully read the terms of service before accepting them BIBREF0 . Additionally, they find that two of the top three factors users reported for not reading these documents were that they are perceived as too long (`information overload') and too complicated (`difficult to understand'). This can be seen in Table TABREF3 , where a section of the terms of service for a popular phone app includes a 78-word paragraph that can be distilled down to a 19-word summary. The European Union's BIBREF1 , the United States' BIBREF2 , and New York State's BIBREF3 show that many levels of government have recognized the need to make legal information more accessible to non-legal communities. Additionally, due to recent social movements demanding accessible and transparent policies on the use of personal data on the internet BIBREF4 , multiple online communities have formed that are dedicated to manually annotating various unilateral contracts. We propose the task of the automatic summarization of legal documents in plain English for a non-legal audience. We hope that such a technological advancement would enable a greater number of people to enter into everyday contracts with a better understanding of what they are agreeing to. Automatic summarization is often used to reduce information overload, especially in the news domain BIBREF5 . Summarization has been largely missing in the legal genre, with notable exceptions of judicial judgments BIBREF6 , BIBREF7 and case reports BIBREF8 , as well as information extraction on patents BIBREF9 , BIBREF10 . While some companies have conducted proprietary research in the summarization of contracts, this information sits behind a large pay-wall and is geared toward law professionals rather than the general public. In an attempt to motivate advancement in this area, we have collected 446 sets of contract sections and corresponding reference summaries which can be used as a test set for such a task. We have compiled these sets from two websites dedicated to explaining complicated legal documents in plain English. Rather than attempt to summarize an entire document, these sources summarize each document at the section level. In this way, the reader can reference the more detailed text if need be. The summaries in this dataset are reviewed for quality by the first author, who has 3 years of professional contract drafting experience. The dataset we propose contains 446 sets of parallel text. We show the level of abstraction through the number of novel words in the reference summaries, which is significantly higher than the abstractive single-document summaries created for the shared tasks of the Document Understanding Conference (DUC) in 2002 BIBREF11 , a standard dataset used for single document news summarization. Additionally, we utilize several common readability metrics to show that there is an average of a 6 year reading level difference between the original documents and the reference summaries in our legal dataset. In initial experimentation using this dataset, we employ popular unsupervised extractive summarization models such as TextRank BIBREF12 and Greedy KL BIBREF13 , as well as lead baselines. We show that such methods do not perform well on this dataset when compared to the same methods on DUC 2002. These results highlight the fact that this is a very challenging task. As there is not currently a dataset in this domain large enough for supervised methods, we suggest the use of methods developed for simplification and/or style transfer. In this paper, we begin by discussing how this task relates to the current state of text summarization and similar tasks in Section SECREF2 . We then introduce the novel dataset and provide details on the level of abstraction, compression, and readability in Section SECREF3 . Next, we provide results and analysis on the performance of extractive summarization baselines on our data in Section SECREF5 . Finally, we discuss the potential for unsupervised systems in this genre in Section SECREF6 .