An interesting read about the trajectory of the impact factor (IF) of PLoS ONE:
There has been a lot of criticism towards the over-reliance on IF as a quantitative metric for researcher evaluation purposes. This article touches on a related point that I hadn’t heard before – to the extent that the distribution of journal impact factors is not uniform across disciplines (some subjects like molecular biology tend to have journals with high IF, while other subjects like crop science tend to have much lower average journal IF), the resulting impact factor of an interdisciplinary journal is potentially distorted, becoming more representative of the range of subjects covered rather than the actual quality of the articles within each of those subjects. This is a potential boon for researchers in low-IF fields: the publication of collaborative work in a broadly-scoped journal might land you a higher-than-average IF to show off on your CV.
For an in-depth analysis of what drives IF trends, check out
Those authors conclude that the IF metric becomes inflated over time as the number of citations included in the average journal article grows, and that much of the discrepancy between fields can be attributed to the rate at which researchers publish in indexed journals as opposed to non-indexed journals or alternate venues such as working papers, conference proceedings, books, etc.
To the extent that many young researchers will one day be evaluated based on their citation rates and the IF of the journals in which they publish, it behooves us to better understand the IF ranking system, flaws and all.