Study on sentence relations in the automatic detection of argumentation in legal cases
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Citation: Raquel Mochales-Palau, Marie-Francine Moens (2007) Study on sentence relations in the automatic detection of argumentation in legal cases. JURIX 2007 (RSS)
Download: http://portal.acm.org/citation.cfm?id=1565624
Tagged: Computer Science (RSS) argument mining (RSS), argument detection (RSS), legal argumentation (RSS), natural language processing (RSS)
Summary:
This builds on the work of Automatic detection of arguments in legal texts; whereas that paper used argumentative texts from multiple domains (including newspapers and social media, despite the title), this work is restricted to the legal domain. Besides detecting argumentative and non-argumentative sentences, premises and conclusions are also detected. Additional features are added to analyze the importance of relations between sentences.
A corpus is annotated then machine learning is used with selected features.
Procedure
29 admissibility reports and 25 legal cases randomly selected by European Court of Human Rights August 2006 & December 2006. These contain facts, complaints, the law, and final conclusions from judges, expressed in long and complex sentences.
These were manually analyzed by two lawyers to indicate whether they contained arguments. There were 12,904 sentences (10,133 non-argumentative and 2,771 argumentative), which included 2,355 premises and 416 conclusions.
Average accuracy of the maximum entropy model is 82%, using only the information from the current analyzed sentence. (Previous experiments used a naive Bayes model; the increased amount of information in this case meant they could not satisfy the independence assumptions of the naive Bayes classifier). They also experimented with using information in adjacent sentences.
In future work they plan to look at the clause level, instead of the sentence level.
Features
These are increased from those used in Automatic detection of arguments in legal texts
- Word couples - All combinations of two words in the current sentence (see Automatic detection of arguments in legal texts for stopwords)
- Text statistics - Argumentative sentences are expected to be longer, with more longer words, and more punctuation
- Argumentative verbs (see Automatic detection of arguments in legal texts )
New features
Previous sentences
- unigrams in previous sentences
- bigrams in previous sentences
- word couples in previous sentence
- adverbs in previous sentence (e.g. "unfortunately")
- verbs in previous sentences (ignoring "to be", "to do", "to have")
- modal auxiliary in previous sentences (modals are more likely in argumentative sentences)
- text statistics in previous sentences (same as above)
- punctuation in previous sentences
- presence/absence 286 argumentative keywords (see Knott & Dale. 1992) in previous sentences
- negative/positive previous sentences (not, don't, won't, ...)
- first/last words in previous sentences (connectors)
- same words in previous & current sentences
Next sentences
- unigrams in next sentences
- bigrams in next sentences
- word couples in next sentence
- adverbs in next sentence (e.g. "unfortunately")
- verbs in next sentences (ignoring "to be", "to do", "to have")
- modal auxiliary in next sentences (modals are more likely in argumentative sentences)
- text statistics in next sentences (same as above)
- punctuation in next sentences
- presence/absence 286 argumentative keywords (see Knott & Dale. 1992) in next sentences
- same words in current & next sentences
- negative/positive next sentences (not, don't, won't, ...)
- first/last words in next sentences (conectors)
- same words in current & next sentences
Related Work/Selected References
Work used
- A. Knott and R. Dale. 1992. Using linguistic phenomena to motivate a set of rhetorical relations. technical Report HCRC/RP39, HCRC Publications, Edinburgh, Scotland.
Linguistic Perspective on Argumentation
- E. Eggs. 1994. Grammaire du discours argumentatif. Editions KIME. -- grammatical structure of French argumentation
- J. B. Freeman. 1991. Dialectics and the macrostructure of arguments: A theory of argument structure. Berlin, New York, Foris Publications.
- I. M. Schlesinger, T. Keren Portnoy, T. Parush. 2001. The structure of arguments. Human Cognitive Processing, 7. Amsterdam, John Benjamins Pub.Co.
Argument Detection
A.C. Restificar, S.S. Ali and S.W. McRoy. 1999. ARGUER: Using argument schemas for argument detection and rebuttal in dialogs. In UM99:Proceedings of the Seventh International Conference on User Modeling, 315317. Banff, Canada. - "studies argumentative speech dialogues and propose a system (ARGUER) that identifies if the user's utterance is attacking or supporting the system last utterance."
Theoretical and practical relevance:
One limitation is that this is non-dialogical, defeasible argumentation, where one issue is being addressed by a given speaker. Further research on dialogical argumentation is needed.
