Garfield and Sher first coined the term "impact factor" (IF) in 1963.¹ An IF, cited as a metric of a journal's rank and influence, is the ratio between the number of research papers cited from a particular journal to the total number of "citable" papers it has published.^2,3 A time bracket of the previous two years is used to calculate the IF for a particular year.³

IF citation has gained popularity on account of its convenience, simplicity of calculation and use.¹ However, many of the readers may not be acclimatized with the factors that must be considered when interpreting it. The type of medical article, the field and discipline of research and the number of articles a journal publishes are all the factors that can influence the calculation of an impact factor.¹ Impact factors are also adjusted for the number of self-citations out of the total number of citations. Also, similar journals should be compared using impact factor as a tool.¹ All in all, there is a competitive cycle of quality and quantity that generates this statistical entity.  

However, IFs are not simple, bland statistical jargon. The implications of IFs for journals stem from the potential of receipt of funding and grants, academic laurels, and scientific influence.¹ With these high stakes, the possibility of manipulation of IFs must also be borne in mind. Some journals have ceased to publish case reports and short correspondences/reports in pursuit of achieving better impact factors; taking some advantage of the inherent flaws in the calculation architecture of the IF.

Over recent years, a lot of criticism has centered on the utility of IF as a true measure of "impact" of scientific research and its misuses have been actively debated on many forums.⁴ At best, IF may only be a limited measure of a journal's scientific acumen and influence because of the potential for misuse and manipulation as well as heavy inclination towards "non-quality" parameters while paradoxically evaluating the quality of journals. There is a need to develop an unprejudiced tool that measures the actual impact of the scientific research on society at large - a "societal impact factor".³

Despite low impact factors, Pakistani medical journals are making commendable contribution to evidence based clinical practice in Pakistan by publication of pre-dominantly indigenous research; no doubt more pertinent, applicable and appropriate for the unique constitution of our population. The level of evidence of articles in two local journals (JPMA and JCPSP) was recently evaluated and reported to compare favorably with international literature.⁵

Taimur Saleem

Student, Class of 2009, Aga Khan University Medical College, Karachi, Pakistan

1.Grzybowski A. The journal impact factor: how to interpret its true value and importance. Med Sci Monit 2009; 15:SR1-4

2.Arfan-ul-Bari. Journal impact factor: still an enigma. J Coll Physicians Surg Pak 2008; 18:458-9.

3.van Driel ML, Magin PJ, Del Mar CB, Furler J, De Maeseneer J. Journal impact factor and its importance for AFP. Aust Fam Physician 2008; 37:770-3

4.Simons K. The misused impact factor. Science 2008; 322:165

5.Chinoy MA, Ahmad T, Tayyab M, Raza S. Evidence based medicine - where do articles published in local indexed journals stand? J Pak Med Assoc 2009; 59:5-9.