IRE Simulation, and simulation experiments chapter Michael D. Heine Butterworth & Company Karen Sparck Jones All rights reserved. No part of this publication may be reproduced or transmitted in any form or by any means, including photocopying and recording, without the written permission of the copyright holder, application for which should be addressed to the Publishers. Such written permission must also be obtained before any part of this publication is stored in a retrieval system of any nature. References 197 generalizes to a broader Systems approach taking in the user's behaviour and even states of knowledge-though such approaches are still in their infancy. Ilecondly, `simulation' as a concept, admittedly an ambiguous one, in its broader definitions comes close to being equivalent to the concept or process that we are seeking to describe in information science. Study of that concept has perhaps a unique significance for us. There are intriguing philosophical problems here. Thirdly, simulation work in its narrower technical senses can aid the management of practical operational systems by helping to arrive at good policies on, for example, depth of indexing, optimum online file size, optimum library back-up, and optimum question definition (using `question' here as a synonym for boolean expression). But the clarifications entailed in describing information systems usefully are difficult to arrive at; so difficult that much, if not most, published work on simulation in the area is fairly disappointing. Fourthly, the work undertaken as part of a simulation study In delimiting and describing a system usually improves understanding of the lystem and suggests hypotheses for further investigation. Lastly it needs to be clearly understood that simulation work, as a species of theoretical work, is always dependent and sometimes critically dependent on valid data from laboratory or operational system studies. Without a continuous stream of 8uch data, reacting symbiotically with simulation/theoretical study, both will be poorer: we will have theory of unproven applicability, and operational 8ystems of unproven optimality. The rationale of the Cranfield experiments must not be lost. References I. CHAPMAN, R. L. The case for information system simulation. In: Proceedings of the Second Congress on the Information System Sciences, 1964, pp.477484, Spartan Books, Washington, D.C. (1965) 2. COOPER, W. 5. Indexing documents by gedanken experimentation, Journal of the American Society for Information Science 29, 107-119 (1978) 3. SALTON, G. (Ed.) The SMART Retrieval System: Experiments in Automatic Document Processing, Prentice-Hall, Englewood Cliffs, N.J. (1971) 4. BARKER, F. H., VEAL, D.C. and WYATT, B. K. Towards automatic profile construction, Journal ofDocumentation 28, 4[OCRerr]55 (1972) 5. VERNIMB, C. Automatic query adjustment in document retrieval, Information Processing and Management 13, 339-353 (1977) 6. HEINE, M. H. The `question' as a fundamental variable in information science. In: Theory and Application of Information Research, Proceedings of The Second International Research Forum in Information Science (Ed. 0. Harbo and L. Kajberg), pp.137-145, Mansell, london (1980) 7. VICKERY, B.C. Information Systems, Butterworths, London (1973) 8. CHURCHMAN, C. W. The Systems Approach, Delacorte Press, New York (1968) 9. MARTIN, F. F. Computer Modeling and Simulating, Wiley, New York (1962) 10. GORDON, G. System Simulation, 2nd edn, Prentice-Hall, Englewood Cliffs, N.J. (1978) II. MORSE, P. M. On Browsing-the Use of Search Theory in the Search for Information, Technical Report No.50, Operations Research Center, MIT (1970) 12. SALTON, G. Dynamic Information and Library Processing, Prentice-Hall, Englewood Cliffs, N.J. (1975) 13. SWETS, 3. A. Information retrieval systems, Science, New York 241, 245-250 (1963) 14. SWETS, 3. A. Effectiveness of information retrieval methods, American Documentation 20, 72- 89(1969) IS. ORR, R. H. et al. Development of methodologic tools for planning and managing library service:II. Measuring a library's capability for providing documents, Bulletin ofthe Medical Library Association 56, 241-267 (1968) II