© 2005 American Thoracic Society
Impact Factor, Impact, and Smoke and MirrorsFrom the Editorialist:I thank Dr. Mannino for his interest in my editorial (1). He is not alone in his criticism of impact factor (2–5). That was the reason I wrote another editorial discussing ten other measures of journal performance (6). Impact factor, however, remains a major determinant of research funding worldwide; only American investigators can afford to dismiss it (3, 4, 7). Dr. Mannino claims that any journal can directly influence impact factor. All editors wish the impact factor of their journal were higher (8–12), but find it difficult to achieve. One mechanism is to increase rejection rate, but this needs to be applied evenly. Throughout the 1990s, rejection rates differed by as much as 30% among AJRCCM associate editors handling a given field (6). To be fair to authors, the associate editors decided to achieve a uniform standard, and rejection rates now differ by less than 3% within and across fields of equal scientific quality (6). In striving for that goal, associate editors decided to raise rather than lower scientific standards. In 2000, AJRCCM published 757 articles, whereas Gastroenterology published 296 articles and Circulation Research published 339 articles. The increase in rejection rate from 50% in 1999 to 75–80% in 2003–2004 brings AJRCCM closer to that of leading journals of other subspecialties, such as Circulation (85% rejection rate). Thorax lists a rejection rate of 87.6% (13) and the European Respiratory Journal is targeting a rejection rate of 75% (11). In considering influences on impact factor, Dr. Mannino omits publication lag—a major determinant because impact factor operates with a 2-year window (5). In 1999, AJRCCM's publication lag was on a trajectory for 10 months (6). It is now 2.5 months. The reason we published 757 articles in 2000 (an increase of 26% over 1999) was to decrease this lag—not a desire for a larger journal, as Dr. Mannino believes. (Indeed, the steady increase in printed pages throughout the 1990s was placing an unsustainable financial burden on the newly constituted ATS [6].) Clearing the backlog, however, prevented the otherwise anticipated increases in impact factor for 2001 and 2002 (5). It is the disappearance of these 757 articles from the denominator for 2003 that caused the abrupt increase in impact factor in 2003 (1). Another issue not mentioned by Dr. Mannino is the discontinuation of industry-sponsored supplements, which constituted more than 12% of articles published in 2000 (and more than 33% of articles on asthma) (6). Dr. Mannino asserts that publishing fewer articles in AJRCCM shortchanges readers. More than 5,000 articles are published every year in the major pulmonary and critical care journals (14). To read these would require more than 25 hours each and every week of the year. A major task of editors is to select those manuscripts most worthy of a reader's time—a focus on quality, not quantity. Dr. Mannino overestimates the contribution of Year-in-Review. The series cites articles from 1 year, whereas the denominator for impact factor is based on number of articles published in 2 years. Accordingly, Year-in-Review caused a one-time increase in impact factor of 0.50 between 2000 and 2001, whereas impact factor increased by 3.433 between 2000 and 2004. Comparing new findings to other recent research is fundamental to scholarship (15). In 2000, however, many papers published in AJRCCM failed to include even one reference from the preceding 10 years. We changed our Instructions for Contributors, requesting authors to use available search engines to bring their references up to date. Year-in-Review is the only search site in pulmonary and critical care that categorizes articles by taxonomic criteria (16), making it more user-friendly. Dr. Mannino implies that AJRCCM is suppressing data on impact factor. On the contrary, all of the numbers that go into the calculation of AJRCCM's impact factor were provided in my editorials (1, 5). There is no smoke. There are no mirrors. All is transparent.
Loyola University Medical School and Hines VA Hospital Maywood, Illinois FOOTNOTES Conflict of Interest Statement: M.J.T. served as editor of AJRCCM from 1999 to 2004, and received a fixed stipend from the American Thoracic Society and was not affected financially by the impact factor of the Journal. He does not receive financial support for research from pharmaceutical, biotechnology, or medical device companies and does not serve as a consultant to or on the advisory board of any company. He receives royalties for two books on critical care published by McGraw Hill, Inc. REFERENCES
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