An Interactive Graph Based Legal Information Retrieval System

A graph based information retrieval framework for the visualization of clusters of related legal documents is proposed. Clusters are obtained through the analysis of the citations and topics of the retrieved documents. Users, interactively, may refine their queries by selecting the graph nodes. Then, the context of the users interaction is calculated and it is shown in a tree-structure. Users are allowed to return to previous interaction states by selecting these tree nodes. This framework was applied to the decisions of the Portuguese Attorney General and it was made available in the web (http://www.pgr.pt — in Portuguese [3]). A detailed example of a user interaction with the system is shown in the paper. An evaluation procedure was applied to the system and it showed a decrease of the average number of interactions per user session.