Reader Comments

Post a new comment on this article

Ending Impact factor discrimination

Posted by plosmedicine on 30 Mar 2009 at 23:56 GMT

Author: Mangesh Thorat
Position: Specialist Registrar, Dept. of Surgical Oncology
Institution: Tata Memorial Hospital
Additional Authors: Priya M Thorat
Submitted Date: July 05, 2006
Published Date: July 5, 2006
This comment was originally posted as a “Reader Response” on the publication date indicated above. All Reader Responses are now available as comments.

Journal impact factor is proportional to the number of times journal articles are cited and is a very reliable scientific literature assessment tool. [1] However, it does not necessarily reflect the real-life impact of literature. In fact, it may reflect the 'Big-Money-Research' content published in a particular journal.

Research in affluent countries focuses largely on diseases like Alzheimer's, Parkinson's, Cancer, Multiple sclerosis etc., attracting huge money, and employing large number of scientists who publish and cite articles on these diseases. As a result, articles in good journals, which focus on publishing this kind of research attract numerous citations inflating their impact factor. However, the impact of such research on the general world population remains meagre.

In contrast, only 10% of overall research is done on diseases affecting 90% of world's population. This results in fewer citations, thus deflating the impact factor of the good journals that publish research on third world diseases. Good research in these diseases saves many more lives, but journals representing the poor score poorly on the impact factor scale. Numerous journals publishing such research are lost in obscurity, seriously impairing the accessibility of scientific knowledge. Will the interest in third world research increase if the impact factor of such journals improves, giving these authors their due scientific status?

To end this rich-poor divide in the scientific literature, clinical journals (not predominantly basic research journals) should be measured on a new additional Clinical Impact Factor (CIF) scale. Each article should be given an incidence-based score (IBS), representing the number of millions affected by that disease. For example, a score of 0.16 for a melanoma paper since it affects 160,000 people annually [2], and a score of 30 for neonatal infections paper since these affect 30,000,000 neonates annually [3]. A total 'journal-wise' annual IBS would be multiplied by the number of citations to get the Clinical Citation Score (CCS), which would form the numerator for calculating CIF.

If feasible, a more accurate method wouldbe an 'article-wise' IBS and CCS. A CIF based on article-wise CCS would stop editors from publishing second-grade research in high-incidence diseases just to improve the IBS of their journal. CIF comparisons will encourage editors to publish good research on third world diseases, thus promoting research in these diseases to eventually decrease research discrimination against these diseases. This will be the real meaning and application of impact factor, to impact rich and poor alike.


1. Garfield E. The history and meaning of the journal Impact Factor. JAMA 2006; 295(1): 90-93.
2. J. Ferlay, F. Bray, P. Pisani, et al. GLOBOCAN 2002 Cancer Incidence, Mortality and Prevalence Worldwide IARC CancerBase No. 5, version 2.0 IARC Press, Lyon, 2004.
3. Stoll BJ. The global impact of neonatal infection. Clin Perinatol 1997; 24(1): 1-21.

No competing interests declared.