Impact Factors of Journals in Sport and Exercise Science, 2004
Will G Hopkins
Sportscience 9, 14-16, 2005
Each year Thomson Scientific (formerly the Institute for Scientific Information) publishes an update of its Journal Citation Reports, which summarize the ways authors of journal articles cite other articles. The statistic of most interest is the journal impact factor, which is the number of times per year the average article in a given journal in recent years (2002, 2003) was cited in all journal articles in the previous year (2004). Impact factors provide only a rough measure of quality of articles in the various journals. For more information and a critique, read the article that accompanied last year's list at this site. The journal Nature, which enjoys one of the highest factors (currently 32), also featured an editorial in June that was critical of "the unhealthy reliance on impact factors by administrators and researchers’ employers worldwide to assess the scientific quality of nations and institutions, and often even to judge individuals".
This year Thomson Scientific insisted that I provide a shorter list of journals and approximate values for some journals, to comply with its policy of acceptable use. I have therefore focused on the core journals of sport and exercise science. I have also had to stop tabulating factors for previous years in this article and to remove tabulations from previous articles. You can access complete citation data at Thomson Scientific's Web of Knowledge, if your institution has a subscription.
In my report for impact factors in 2003, I noted that the typical change in the impact factor between years was ~±0.3. Assuming a change greater than 0.3 is therefore atypical or noteworthy, the following core journals showed noteworthy increases since last year: Acta Physiologica Scandinavica (1.7®2.1), Journal of Rehabilitation Medicine (1.1®1.6), Leisure Sciences (0.7®1.3), Pediatric Exercise Science (0.8®1.4), Physical Therapy (1.6®2.0), and Sports Medicine (2.4®2.8). The biggest winner is the Scandinavian Journal of Medicine and Science in Sports, up from 0.9 to 1.7. Exercise and Sport Sciences Reviews made a respectable entry on 2.3, after the requisite three years since its first appearance as a journal. Two core journals showed a noteworthy decline of more than 0.3: Clinical Journal of Sport Medicine (1.8®1.4) and Journal of Sports Sciences (1.3®0.9).
I doubt whether the changes in specific journals reflect changes in quality of the articles therein. More likely, the changes are due either to sampling variation, or to changes in the area of specialization of the journal, or to changes in research activity in the journal's discipline. It worries me that a fall in a journal's impact could result in a vicous cycle of decline, because some researchers may save their best work for journals that are on the way up. My continuing to publish these factors from year to year might help set such a vicious cycle in motion. Publishing this article is also inconsistent with my critical view of impact factors, but my motives are partly selfish: the article is easy to write, it is popular, and it may serve as a magnet to attract readers to the other articles.
In the table below, "<1.0" implies a value between 0.1 and 1.0. Journals without an impact factor are not in ISI's science or social sciences databases, either because the journal is too new or the factor is too low.
Thomson Scientific, Inc. is the
publisher and copyright owner of the Journal Citation Reports®.
Published Dec 2005