Ah, impact factors. I think that most journal editors would rather do without them. The Institute for Scientific Information annually ranks about 8000 journals.1 These are grouped into about 200 categories, such as allergy, emergency medicine and critical care, and developmental biology. This is done in part because citation practices vary across disciplines;2,3 the categories represent an attempt to partly standardize the results. For example, in the geriatrics and gerontology category the leading journal has an impact factor of 3.4, whereas in the immunology category the leading journal has an impact factor of 47.6.1 CMAJ is in the category of medicine, general and internal. When reviewing information on impact factors, we compare ourselves with similar journals. Thus, in the CMAJ article Etminan refers to, we ranked ourselves against other general medical journals.4 The Annual Review of Medicine, which publishes 1 issue per year and contains only review articles, is not a general medical journal.
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John Hoey
References
- 1.Institute for Scientific Information. 1999 journal citation reports. Philadelphia (PA): The Institute; 2000.
- 2.Joseph KS, Hoey J. CMAJ's impact factor: room for recalculation. CMAJ 1999;161(8):977-8. [PMC free article] [PubMed]
- 3.Garfield E. Journal impact factor: a brief review. CMAJ 1999;161(8):979-80. [PMC free article] [PubMed]
- 4.CMAJ's impact factor improves. CMAJ 2000; 163(9):1182.