Impact Factors of Journals in Sport and Exercise Science, 2000-2003
Will G Hopkins
Sportscience 8, 12-19
Each year the Institute for Scientific Information (ISI) publishes an update of its Journal Citation Reports, in which are summarized the ways authors of journal articles cite other articles. Interest centers most on the journal impact factor, which is the number of times the average article in a given journal has been cited lately. Specifically, the most recent impact factor for a given journal is the number of times authors of articles in all journals for the year 2003 have cited articles in issues of the given journal for 2001 and 2002, divided by the number of articles in the journal for those two years.
For journals specializing in a particular discipline, the impact factor is partly a measure of a journal's popularity and quality, but it is also partly if not largely a measure of the number of researchers active in the discipline. As sport scientists, I therefore believe we should resist the penchant of some academics and administrators to regard the impact factor as a measure of quality alone and to rate our research by the impact factor of the journals we publish in. We do your research to improve the quality of service we can deliver to athletes, patients and clients, not to impress administrators by scoring a hit in a popular journal. Publication serves the dual useful purposes of getting the job finished properly and of getting the findings where others can use them, but it is not an end in itself.
My In-brief item at this site last year has more information about the impact factor. Steve Olivier, one of the reviewers of this article, also suggested this link to a detailed critique of the impact factors. The other reviewer, Rob Robergs, suggested I point out that the impact factor may be inflated by articles that get cited frequently because they are bad, not because they are good.
Although I am critical of the abuse of impact factors, I know that the topic excites great if undeserved interest amongst researchers. I have therefore once again provided a summary of the factors for exercise and sport science (Table 1). You can access impact factors for other journals and other citation-related statistics at the ISI site, but only if your institution has a subscription.
As in previous years, the list shows that the average recent article in journals focused on athletic performance research is cited about once a year. You and your administrators and funding agencies should therefore realize that any journal with a factor in the ~0.5-2.5 range is a perfectly reasonable outlet for such work. A few journals outside this range are also reasonable outlets, but for the others there is an increased risk that researchers and practitioners will not find, read, cite or otherwise use work published in them. I have also again provided the impact factors for the last few years, because a change in a journal's impact factor may a useful measure of a change in quality or focus. Rob Robergs suggested that this assertion was inconsistent with my earlier criticism of the impact factor, but I think the impact factor is like skinfold thickness: not good as an absolute measure of body fat, but much better for tracking changes in body fat.
This year there are several noteworthy impact factors. The Journal of Science and Medicine in Sport has at last entered the list and with a respectable 0.7. The Journal of Applied Physiology has reached 3.0 for the first time, perhaps reflecting movement away from applied science towards academic research focused primarily on mechanisms. Medicine and Science in Sports and Exercise is holding steady on 2.6 at the top of our applied journals. Its higher factor may derive in part from its review articles. The most popular exclusively review journal specific to our discipline is Sports Medicine, which has been inching upwards over the last few years and is now on 2.4. Most other journals have held steady within ±0.2 of last year's factor, but two have shown substantial falls of 0.3 or more: Journal of Sport and Exercise Psychology and Research Quarterly for Exercise and Sport.
Exercise and Sports Sciences Reviews is still not on the list, because it changed from book to journal format in 2000, ISI did not accept the journal for evaluation until 2002, and ISI needs three years to calculate a new impact factor. European Journal of Sport Science, International Journal of Performance Analysis in Sport, Journal of Exercise Physiology-online, and Journal of Sports Science and Medicine are exclusively on-line journals that have yet to make it to the list. The new editor of EJSS (Asker Jeukendrup) assures me that he is taking a tough line with submitted material, that the journal is not a dumping ground for manuscripts rejected elsewhere, and that it will inevitably get an impact factor. Whether Sportscience, another on-line-only journal, will ever make it to the list is unclear. Its impact as a resource for research students and researchers may well be greater than that of mechanism-focused journals. The editor has now instituted page numbers rather than the more rational URL and word count, because some journal editors automatically exclude citations to websites from the reference list of a submitted article (see this issue's editorial).
See the Abstract for a summary of the impact factors of the main journals, and see Table 1 for the complete alphabetical list of journals and factors since 2000. Some specialist journals on the fringe of our discipline and some popular generic journals like Nature (impact factor 30) and Science (30) are included by special request of readers in previous years. Physiological Reviews (37) has beaten these journals and New England Journal of Medicine (35) into first place for the first time.
Rob Robergs, who is the editor of Journal of Exercise Physiology-online, offered the following comments for inclusion in this article…
It is also important to realize what the conditions of submission to and acceptance by ISI are. A submission is reviewed by “experts” of the academic area, which has the potential to foster considerable bias in journal selection. Also, the ISI system favors traditional publishers. A new system is being developed for assessing the impact of electronic journals. This new dimension to the science citation and electronic database search arena may make the ISI system redundant for journals such as JEPonline, Sportscience and EJSS. By definition, free-access electronic journals have a far greater circulation than printed journals, and their readership is not represented by any ISI citation statistic.
Wouldn’t a more valid method of impact-factor calculation be based on the number of times a journal article is read? After all, as you state early in your article, it is not whether the article is cited, but whether it is read that best reflects the main objective of publication: that peers get to read the article. Our electronic journals have far greater potential to achieve this aim than traditional journals. Some measure of the hits a journal and its articles get should provide a valid measure of readership-based impact.
Nov 2004. Updated Dec 2 2004.