Similarity Analysis of Legal Judgments and applying 'Paragraph-link' to Find Similar Legal Judgments.

With technological advancements, more and more content is becoming available in digital form on a regular basis. Such overwhelming amount of available data has lead to the problem of information overload. This has led to an increased interest in developing methods that can help users to effectively navigate, summarize and organize this information. The ultimate goal is to help users find what they are looking for. Significant efforts have been made to encounter challenges posed by information overload in web-domain. These efforts include exploitation of text-content as well as links (present as URL in web-pages). Interestingly, phenomenon of data explosion isn’t limited to web-domain but also observed in various other domains as well. Though the nature of challenges induced by information load is quite the same across all domains, uniqueness of a domain demands specialized solution. Unsurprisingly, efforts have been made to build information retrieval system in other domains by extending the popular notions developed for web-domain retrieval systems. In this thesis, we made an effort to address one of the challenges in legal domain and investigated the problem of finding similar legal judgments. In legal domain, information overload has adverse effect on finding similar judgments, which is a crucial task for a lawyer to prepare his arguments. Due to enormous number of judgments available, a lawyer needs to browse through hundreds of legal judgments to find a set of legal judgments similar to a given judgment ‘J’ and hence finds this task tiring and time consuming. In order to find similar legal judgment, he starts browsing legal database using his knowledge and experience. Once he finds an older judgment (say judgment ‘J’) which adequately satisfies his requirements, he starts looking for more judgments similar to judgment ‘J’ for comprehensive analysis of the legal principle applied in those judgments. Since number of judgments in legal database is enormous and, in general, size of each judgment is huge, an automated mechanism for finding similar legal judgments turns out to be a non-trivial problem. Textual information and its accessibility play a particularly important role in legal domain. The amount of available text-data in legal domain is vast and continuously growing which makes it challenging to deal with. Apart from the size of data, the inherent complexity of legal domain demand better and more sophisticated methods to process legal documents to satisfy information need of legal practitioners. To begin with, we investigated the issue of finding similar legal judgment by exploiting various attributes of legal judgments. We conducted our experiment on real world dataset and found that, textcontent of judgments is not as effective as links (known as case-citations) available in legal-judgments, for finding similar legal judgments. Further investigation showed that, the performance of case-citation as similarity measure extracts small number of similar judgments from the corpus of judgments. This phenomenon was observed due to availability of less number of case-citations in judgments. Therefore, sole dependency on casecitation to find similar judgments isn’t enough. In order to improve the performance, we proposed the notion of ‘paragraph-link’. We exploited content-based similarity approach to apply ‘paragraph-links’ and then applied link-based measure to find similar judgments. It was found that, the new approach produces encouraging results and improves the performance of the previous approach.