Changes in the Use of Literature with Time--Obsolescence Revisited

THE1974 ARTICLE BY Line and Sandison entitled “ ‘Obsolescence’ and Changes in the Use of Literature with Time” was highly critical of many assumptions about obsolescence and of the methodology and conclusions of much research on the topic. It placed emphasis on the distinction between synchronous and diachronous studies and on the need to correct for the size of the literature cited or used. Since that date, there has been a good deal more discussion of the matter, and additional light has been shed on the theory, but much research remains to be done, unwarranted statements continue to be made, and there has been little contribution to the practical applications of literature use decay. Citation studies confirm the great variation in citation decay between subjects and types of article and also show that the sources used for citations affect the results of analyses. Libraries are under greater pressure of space, but most models are too complex and time-consuming for them to use. Libraries tend not to collect data on use before weeding, and there have been few use studies. However, automated systems should now make it possible to gather relevant data. If and when the “virtual library” comes into being, remote access may make weeding easier because wrong decisions may be reversible, but several conditions have to be met before this makes much practical impact. INTRODUCTION In 1974, an article by Sandison and myself was published with the title “‘Obsolescence’ and Changes in the Use of Literature with Maurice B. Line, 10 Blackthorn Lane, Burn Bridge, Harrogate, England HG3 1NZ LIBRARY TRENDS, Vol. 41, No. 4, Spring 1993, pp. 665-83 @ 1993 The Board of Trustees, University of Illinois 666 LIBRARY TRENDS/SPRING 1993 Time” (Line & Sandison, 1974). It reviewed all the literature on the subject that we could find and came to some interesting and unorthodox conclusions. It has been widely cited and has become something of a classic. This article looks selectively at subsequently published literature that deals with the issues we discussed earlier with particular reference to the practical implications for libraries. It goes on to examine the relevance of the concept of obsolescence in a possible future world where libraries are “virtual” rather than