ISR11 Design Criteria for Automatic Information Systems chapter M. E. Lesk G. Salton Harvard University Gerard Salton Use, reproduction, or publication, in whole or in part, is permitted for any purpose of the United States Government. v-36 future information centers will make use of automatic text analysis rather than manual subject indexing. Among the techniques likely to be implemented in practice are the synonym recognition and phrase generation methods made possible by thesauruses and phrase dictionaries, and the statistical term-term association procedures. Document identifiers may be expected to be based on document abstracts, or longer document excerpts, and weights will be assigned to improve retrieval performance. A variety of additional techniques including expansion by subject hierarchies and automatic syntactic analyses may be used under special circumstances but their general applicability is still unproved. Acknowledgement: The assistance of Mr. Cyril Cleverdon and Mr. Michael Keen of the Aslib-Cranfield Research Project in making available the Cranfield documents and dictionaries is gratefully acknowledged.