Changes in the use of literature with time: obsolescence revisited

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.

Abstract

THE 1974 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.