Journal
Impact Factors in Sport and Exercise Science, 1999–2000 Will G Hopkins Department
of Physiology and School of Physical Education, University of Otago, Dunedin
9001, New Zealand. Email. Sportscience
5(3), sportsci.org/jour/0103/wghimp.htm, 2001 (2164 words) Reviewed by Frank I Katch, Department of
Exercise Science, University of Massachusetts, Amherst Ma 01003 The impact
factor of a journal is the number of times its average recent article was
cited annually in recent publications.
It is a measure of the importance of a journal that researchers should
consider when submitting material for publication. I present here an analysis
of impact factors of journals in exercise and sport science for the years
1999 and 2000. The uncertainty in the impact factor for journals like Medicine
and Science in Sports and Exercise (MSSE, current impact factor of 2.6)
is probably less than ±0.2 (95% likely limits). Journals with an impact
factor in the range 1.0 to 4.9 in 1999 showed little overall increase in 2000
(mean, 0.1), but wide variation existed between journals (standard deviation
of change, 0.5). MSSE's rise of 0.5
since 1999 is therefore well above the average change. Reprint pdf · Reprint doc KEYWORDS: citation, ISI, MSSE, publication |
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At the
end of each year the Institute for Scientific Information (ISI) publishes its
Journal Citation Reports for
science and social science journals (ISI, 2001). The most interesting feature of the reports
is the journal impact factor, a measure of the importance of each journal.
The impact factor for a journal is roughly the number of times per year the
average paper in the journal was cited in any recent journal. More precisely, the impact factor for the
year 2000 (the current impact factor) is the number of times articles in the
journal for the years 1998 and 1999 were cited in ISI-recognized journals
published in 2000, divided by the number of articles in the journal in 1998
and 1999. At the ISI website there is
a page of detail about this statistic and others for each journal. You can
link to these pages only if your institution has a subscription to the Web
version of the journal citation reports. Your library may also/instead have a
hard copy of the reports. A
researcher building a career in a traditional academic setting should take
impact factors into account when submitting material for publication, because
publishing in high-impact journals will enhance the researcher's chances of
appointment and promotion. A
researcher in a more applied setting may have to find other ways to get
recognition for productivity, because the often-used case-study qualitative
reports and materials that benefit students, clients, and communities usually
do not qualify for publication in ISI-recognized journals. Table 1 summarizes the impact factors for journals of
interest to researchers in exercise and sport science. The table includes impact factors for 1999,
culled from an article about the impact factor
published at this site last year (Hopkins, 2000). Some academics are
interested in rank-ordering journals by impact factor, so I have provided the
table as an Excel spreadsheet containing columns for various sub-disciplines
of exercise and sport science. Download the spreadsheet and sort it
by sub-discipline and/or impact factor to make comparison of journals
easier. Be aware that
discipline-specific original-research journals such as MSSE will never score
as highly as the generic high-flyers like Science and Nature or
the review journals that overlap with more well-funded disciplines like
genetics, molecular biology, medicine, and neuroscience. Some
academics also keep on eye on changes in the impact factor of their favorite
journals. In doing so, they should
take into account the magnitude of the typical error of measurement of the
impact factor, and the mean and typical variation of the change in impact
factor of all related journals. In what follows, I demonstrate how to assess
the change in impact factor between 1999 and 2000 for MSSE, one of our key
journals. The
impact factor refers to a number of citations divided by a number of
articles, so the error in the impact factor will depend on these numbers
(which are known) and on the correlation between them (which is
unknown). The correlation will always
be positive and will always reduce the error, so I obtained a conservative
estimate of the error by assuming a correlation of zero. The error for MSSE's current impact factor
of 2.6 turns out to be less than ±0.1, and the 95% likely limits of the true
impact factor are therefore less than ±0.2.
I conclude that the improvement from MSSE's value of 2.1 last year is
clear cut. The question then arises as to the magnitude of the change. By
analyzing the impact factors for 1999 and 2000 in Table 1 with the reliability spreadsheet at
this site, I determined that journals with impact factors between 1.0 and 4.9
in 1998 showed an increase of 0.1 ± 0.5 (mean ± standard deviation). MSSE's increase of 0.5 therefore compares
well with other journals on the rise, but it is not exceptional: of the 93
journals with impact factors in the 1.0–4.9 range, 14 had a larger increase
than MSSE and 78 had a smaller increase or a decrease.
Hopkins
WG (2000). Impact factors of journals in sport and exercise science.
Sportscience 4(3), sportsci.org/jour/0003/wgh.html (1592 words) Institute
for Scientific Information (2001). 2000 journal citation reports (science and
social science editions). Philadelphia, PA: ISI |
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