Impact factor impacts on early-career scientist careers

When I was named the new Editor-in-Chief of PNAS in October 2018, I received hearty congratulations from colleagues from a wide range of disciplines, befitting the intended audience of this venerable journal. The appointment is not my first experience serving as Editor-in-Chief; in 2017, I stepped down after 21 years as Editor-in-Chief of the Annual Review of Entomology (ARE). Although ARE is known in entomological circles as the most highly cited journal in the field, even my entomological colleagues readily acknowledge that PNAS is considerably more influential. By one widely used metric, however, the change could be seen as a step down; the impact factor of the last volume of ARE I edited, 13.860, was higher than the impact factor, 9.504, of the journal whose editorial ranks I had just joined. May R. Berenbaum. The irony of the comparison is not lost on me, and I’m hardly the only person who finds journal impact factors (JIF) troubling, even when their values are not calculated to the third decimal point. I’m not even the first person to express concerns about JIF within the pages of PNAS. Four years ago, former Editor-in-Chief Inder Verma (1) cautioned the scientific community against relying on JIF as a surrogate for the quality of any individual article. Before that, Alan Fersht (2), in introducing an alternative metric to readers, reported that, of 39 different bibliometric scales of ranking journals, the impact factor was “at the periphery” (p. 6883). The first to criticize JIF may well have been the person who invented the metric. Although legendary information scientist Eugene Garfield created the concept of science citation analysis in 1955 (3), he did not expand the idea of using “journal impact factor” to evaluate the relative “importance” of a journal until 1972 (4). His concept was to use …