Using the literature of human and medical genetics, the results of a synchronous citation study of obsolescence over a 19-year period were compared with the results of a di achronous citation study...

Synchronous versus diachronous methods in the measurement of obsolescence by citation studies

The publication age or date of documents used (or not used) has long fascinated researchers and practitioners alike. Much of this fascination can be attributed to the weeding opportunities the data is thought to provide for libraries in their never-ending battle to find the space to accommodate their expanding collections. In general journal article age studies have shown an initial increase in use/citation, then a gradual or sharp decline, depending on the discipline concerned. This characteristic has been termed obsolescence or decay and was largely measured, in the absence of accurate journal usage/borrowing data, by citations. In the sciences the decay rate was shown to be the greatest. This was largely put down to the rapid obsolescence of much scientific content. New research findings, methods or ensuing events rendered the material obsolescent. Of course, when reviewing the data we need to be reminded of the fact that citation studies reveal ‘‘use’’ by authors, whereas library loans or downloads represent actual use by readers, and it is readers that libraries and digital libraries principally target. Clearly the fall of in use with time must have also been a function of the way that libraries arranged their material (in reverse chronological order); a lack of time and patience will inevitably result in readers aborting their searches after a few years and those few years will be the most recent ones. Similarly, it must also have been a function of the difficulties of searching hard-copy back volumes/issues in libraries over time.

Revisiting 'obsolescence' and journal article 'decay' through usage data: an analysis of digital journal use by year of publication

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.

https://www.ideals.illinois.edu/bitstream/handle/2142/7869/librarytrendsv41i4i_opt.pdf?sequence=1

Changes in the use of literature with time: obsolescence revisited

This study explores the in‐house use age distribution of journals in the library of Veterans General Hospital, Taipei, Taiwan, their citation age distribution and the difference between them. The use study employed the sweep method and the study period lasted for six months. The citation age of each journal in this study was based on the data listed in the Science Citation Index, Journal Citation Reports, 1993. The results of this study illustrate that the use age distribution for the mean of all the journals is an exponentially decaying curve. On the other hand, the citation age distributions show a sharp initial rise from age one to three or four years and then fall off in a sort of exponential decay; and the age of maximum citation is typically three years. About 80 per cent of uses are attributed to journals less than ten years old, while these journals contribute about 70 per cent of total citations. The Kolmogorov‐Smirnov two‐sample test indicates that the use age distribution does not fit the citation age distribution.

Library journal use and citation age in medical science

This is a paper about research designs in information science. We look at a sample of current research and compare its designs with an abstract ideal of experimental research design to see how closely they approximate it. We then consider ways in which research in our field might be brought closer to the ideal. We do this because we believe that experimental and quasi-experimental designs offer unique advantages over other research designs, especially in the production of knowledge that can be applied to the solution of practical problems in information and in software science.

Michael V. Sullivan

Papers

Obsolescence in Biomedical Journals: Not an Artifact of Literature Growth.