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Journal Impact
Factor
Brig Azhar Mubarik*
Eugene Garfield of Institute of
Scientific Information (ISI) of Philadelphia, USA introduced Journal
Impact Factor (IF) in 1960. The impact factor is calculated every year
from 17000 science and social sciences journals indexed by ISI. The
calculation of Impact factor is based upon citation of various papers
published by that journal during the two previous years. It indicates
how many times the papers published in a journal are cited by others in
their articles.1
For example, the 2005 impact factor for a journal can be calculated as
follows:
* The number of articles published in a journal during 2003 and 2004,
which were cited in all ISI indexed journals during 2005.
* The total number of articles, reviews, proceedings or notes published
in the same journal during 2003 to 2004.
The IF of the journal for 2005 will be = A/B.
The impact factors and indices are published in Journal of Citation
Reports (JCR) every year.2 The IF of some of these journals out of 6088
journals published in 2005 are shown in the table.
The IF is the gauge of the quality of various journals. Higher the
impact factor, greater is the prestige of that journal. IF provides
quantitative tool for ranking, evaluating, categorizing, and comparing
various journals. The most important application of IF is its weightage
in academic appointments. IF has a huge, but controversial, influence on
the way published scientific research is perceived and evaluated.3
What are the controversies regarding IF?. The opponents of IF argue that
few non-English journals are indexed by ISI. Delay in processing of an
article causes outdating of research therefore less citation. Journals
containing more review articles have greater citation, therefore higher
impact factor. Others complain that the temporal window for citation is
too short, therefore classic articles cited frequently even after
several decades are not included in the citation, thus does not affect
the IF of that journal. Example of super-citation classic includes the
Lowry method4 cited 300,000 times. Furthermore self citation is
encouraged by editors to improve the IF of that journal.5 A recent
debate on the World Association of Medical Editors (WAME) Listserv also
highlighted the fact that how some journals try to manipulate their
Impact Factor. 6
As evident from the table no biomedical journal of Pakistan has any IF
and therefore cannot be compared with any international journals.
Ideally the local journals should try to get in themselves indexed with
ISI and acquire an impact factor.7 At present just one, Pakistan Journal
of Medical Sciences is covered by the Science Citation Index Expanded (SCIE)
by ISI/Thompson which has just been approved in April 2007. Inclusion of
more Pakistani medical journals at the moment seems very difficult at
present. Currently 36 biomedical journals are recognized by Pakistan
Medical and Dental Council (PMDC) and they give equal importance to all
of them. This is not fair as some of these journals are of very high
standards and indexed in Index Medicus, whereas others have variable
standards. Therefore we must devise a system similar to IF for local
biomedical journals so that authors publishing in better journals may be
given preference over those who get their papers published in low
standard journals. There are a number of institutions which can take
this responsibility, like Higher education Commission of Pakistan, PM&C
or College of Physicians and Surgeons Pakistan. Impact can also be
calculated, like Citation index, which shows the number of times an
article is cited by others.8
Other measures of impact of a journal are now under active
consideration. The examples include PageRank algorithm, H-Index and The
F1000 factor. 8,9
Page Rank algorithm: J. Bollen et al proposed it in 2006. Page Rank
algorithm is used by Google to distinguish the quality of citations and
hence improve the Impact Factor.
H-Index: 8 It seeks to describe the impact of individual researchers,
rather than journals.
The F1000 Factor.10 The Faculty of 1000 medicine evaluates and comments
on the most interesting papers they read each month. They assign a
rating: “Recommended” (F1000 factor 3.1), “Must read” (F1000 factor
6.2), “Exceptional” (F1000 factor 10.7)
References
1. Garfield E, Sher IH. New
factors in the evaluation of scientific literature through citation
indexing. American Documentation 1963;14(13):195-201.
2. Institute for Scientific Information. Journal Citation Reports: A
bibliometric analysis of science journals in the ISI database.
Philadelphia: The Institute; 1993.
3. Saha S, Saint S, Christakeis DA. Impact factor: a valid measure of
journal quality? J Med Libr Assoc 2002;91(1):42-6.
4. Lowry OH, Rosenbrough NJ, Farr AL, et al. Protein measurement with
the folin phenol reagent. J Biol Chem 1951;193:265-75.
5. Mohd HF, Van Leeuwen TN. Impact factors can mislead. Nature
1996;381:186.
6. Jawaid SA. How some journals manipulate the Impact Factor. (Off the
Record) 2006;7(21):1-9. (Based on disussion on World Association of
Medical Editors WAME-L@LIST.NIH.GOV)
7. Garfield E. How can impact factors be improved? Br Med J
1996;313(7054):411-3.
8. H-index calculator for an individual scientist’s impact. Available
from: URL http: / /
www.epidemiology.Org/2006/12/h-index-calculator-of-scientist-impact.html
9. Jafary MH, Jawaid SA. How relevant are Impact Factor and Indexation
in Medline. Editorial. Pak J Med Sci 2007;23(1):1-3.
10. www.f1000medicine.com
* Professor of Pathology,
Army Medical College, Rawalpindi - Pakistan.
Editor,
Pakistan Armed Forces Medical Journal,
E-mail:
azhar_histopath@hotmail.com |
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