The Impact Factor and Orthopaedic Research
Marcus Timlin A.F.R.C.S.I.
(Registrar in Orthopaedic Surgery)
Address for Correspondence:
Publish or Perish we are told from the beginning of our training as doctors. Aside from these competitive times for junior orthopaedic trainees and consultants to be, there is a duty upon us all as orthopaedic surgeons to keep ourselves informed of current orthopaedic knowledge and to play an active role in contributing to the knowledge base of orthopaedics.
We are obliged as surgeons and scientists to publish our research in peer reviewed journals. Naturally we would like our research to have thewidest possible impact. In this article we explore the notion of "impact factor" and give some opinions regarding the impact factor of orthopaedicjournals to guide us in choosing the most appropriate journal for our research.
The Impact Factor:
The impact factor was first mentioned by Eugene Garfield in 1955 and bothhimself and Irving Scher created the journal impact factor to help select journals for the Scientific Citation Index (S.C.I.).. The Institute for Scientific Information (I.S.I.) publishes the Scientific Citation Index annually. They perform a bibliographic analysis of approximately 6,000 scientific journals each year and use this data to publish the Journal Citation Reports. These help us to answer what are the largest journals, what journals are used most frequently, what are the "hottest" journals, what journals have the highest impact and finally what publications does a journal site and which site it? .
The institute for Scientific Information have devised an "impact factor" which is a measure of the frequency with which an "average article" in a journal has been cited in a particular year. The impact factor is calculated by dividing the number of all citations of articles published in the journal during the previous two years by the number of articles published in the journal in those two years. Using the BMJ as an example: the number of citations of BMJ articles in all journals in 1999 to articles published in the BMJ in 1997 and 1998 = 9062, the articles published in the BMJ in 1997 and 1998 = 1762, the impact factor is therefore 9062 divided by 1762 = 5.143. In short, the impact factor is the average number of citations generated by an article published in the journal.
Critical Analysis of The Impact Factor:
There are disadvantages and limitations to the current system. There is a bias from editors who know the submitting authors. There is the "padding effect" whereby a group of scientists dominating a field of research only cite one another.. The "halo effect" is when scientists who hold prominent positions in prominent universities are more likely to be published. .
The most distressing negative element is that potentially brilliant research from an unknown scientist or institution may not be recognised. Two note worthy examples of this are firstly the work of Alan Cormack who was awarded the Nobel Prize for physics for research that led to the CAT scanner. His work was published in an obscure journal of unknown impact factor which had only two requests for reprints. Secondly, arguably the greatest scientific discovery of this century was Watson and Crick’s discovery of the structure of DNA, not so according to its impact factor! .
The Scientific Citation Index ranks its "source" journals from approximately 6,000 of some 70,000 journals published worldwide. The impact factor is not a perfect tool to measure the quality of articles but there is nothing better and it has the advantage of already being in existence and is therefore a good technique for scientific evaluation. Experience has shown that in each specialty the best journals are those in which it is most difficult to have an article accepted and these are the journals that have the highest impact factor. These journals existed long before the impact factor was devised. The use of the impact factor as a measure of quality is widespread because it fits well with the opinion we have in each field of the best journals in our specialty. .
The Impact Factor and Orthopaedic Journals:
Armed with our information about impact factors we are now ready to attack the orthopaedic journals with our research. I will firstly list the top twenty orthopaedic journals (or journals that readily accept orthopaedic papers) with their respective impact factors.
Journal Impact Factor:
Lest we look upon The Irish Journal of Medical Science or Injury with disdain we must note the impact factors of some real high flyers, Cell (39.191), Nature (25.466), NEJM (22.673), Science (22.087). It is also noteworthy that our general surgical colleagues have only two journals with impact factors higher than our number one in their top twenty.
It is essential we target
our journals while performing, if not before performing our research.
I have already mentioned the importance of the impact factor for the
consultant interviews but also when submitting research proposals for
funding the impact factors of your previous research will be calculated.
A helpful web page with a list of the majority of the orthopaedic journals
and links to their relevant WebPages and instructions to authors
In conclusion research that is not published in any form has no impact. Research that is presented at conferences has limited and ephemeral impact. Research that is published in an archived journal, even with a lowly impact factor, is a contribution to scientific posterity, the impact of which will be available for years to come.