Journal of Documentation, Vol. 54, No. 4, September 1998
© Aslib, The Association for Information Management.
All rights reserved. Except as otherwise permitted under the Copyright, Designs and Patents Act
1988, no part of this publication may be reproduced, stored in a retrieval system, or transmitted in
any form or by any means, electronic, mechanical, photocopying or otherwise without the prior
written permission of the publisher.
Aslib, The Association for Information Management
Staple Hall, Stone House Court, London EC3A 7PB
Tel: +44 (0) 171 903 0000, Fax: +44 (0) 171 903 0011
Email: pubs@aslib.co.uk, WWW: http://www.aslib.co.uk/aslib
A NEW CLASSIFICATION SYSTEM TO DESCRIBE THE AGEING OF
SCIENTIFIC JOURNALS AND THEIR IMPACT FACTORS
H
.
F
.
MOED
+
moed@cwts.leidenuniv.nl
TH
.
N
.
VAN LEEUWEN
+
leeuwen@cwts.leidenuniv.nl
J
.
REEDIJK
++
reedijk@chem.leidenuniv.nl
+
Centre for Science and Technology Studies (CWTS), Leiden University
PO Box 9555, 2300 RB Leiden, The Netherlands
++
Leiden Institute of Chemistry, Leiden University, PO Box 9502
2300 RA Leiden, The Netherlands
During the past decades, journal impact data obtained from the
Journal Citation Reports (JCR) have gained relevance in library
management, research management and research evaluation. Hence,
both information scientists and bibliometricians share the responsi-
bility towards the users of the JCR to analyse the reliability and
validity of its measures thoroughly, to indicate pitfalls and to
suggest possible improvements. In this article, ageing patterns are
examined in ‘formal’ use or impact of all scientific journals
processed for the Science Citation Index (SCI) during 1981–1995. A
new classification system of journals in terms of their ageing charac-
teristics is introduced. This system has been applied to as many as
3,098 journals covered by the Science Citation Index. Following an
earlier suggestion by Glänzel and Schoepflin, a maturing and a
decline phase are distinguished. From an analysis across all subfields
it has been concluded that ageing characteristics are primarily
specific to the individual journal rather than to the subfield, while the
distribution of journals in terms of slowly or rapidly maturing or
declining types is specific to the subfield. It is shown that the cited
half life (CHL), printed in the JCR, is an inappropriate measure of
decline of journal impact. Following earlier work by Line and
387
THE
Journal of Documentation
VOLUME 54 NUMBER 4 SEPTEMBER 1998
387
Journal of Documentation, vol. 54, no. 4, September 1998, pp. 387–419