An information retrieval system (as distinguished from a document retrieval system) is described for handling statute-oriented legal literature. The Normalized Sentence-Index Matrix (N-SIM) system suggested differs from more traditional retrieval systems for legal literature in three respects: (1) the categories used for classification are normalized versions of sentences from statutes, regulations, treaties, constitutions, case opinions, legal treatises, law review articles, and other documents in legal literature, (2) the classification system is hierarchial and open-ended to evolve with the literature through time, and (3) the organization of the file facilitates some analysis of the literature by computer. A sentence is expressed in implicative normal form (INF) when three specified conditions are fulfilled. Statutory norms are converted into INF before being stored in the N-SIM file. Negative implicative normal form (NINF) is also defined, and all assertions in legal literature about aspects of the statutory norms are converted into either INF or NINF for storage in the N-SIM file. The N-SIM file is designed so that it can be used manually as a loose-leaf service or in a system of automatic data processing by machine. It is hypothesized that statutes expressed in this normalized form will be understood by various audiences of readers both more quickly and more accurately than statutes expressed in their current form. A method for empirically testing this hypothesis is suggested.
Allen, Layman E. "A Language-Normalization Approach to Information Retrieval in Law." Jurimetrics 9 (1968): 41-56.