2012 Impact Factors – Mol Ecol does well, ME Resources blows the roof off

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When ME Resources switched to publishing Primer Notes in a summary article back in 2009, I had a strong hunch that our 2012 Impact Factor could go up quite a bit – this is the first year that the IF was calculated from two years (2010 and 2011) where we published no stand-alone Primer Notes.

At the time I thought a figure like 5.0 was possible, but we actually ended up with 7.42. A lot of this is due to the very high citation rate of Laurent Excoffier et al.’s 2010 update of Arlequin (529 citations in 2012), but even excluding this paper our IF would have been something like 5.5. Ultimately, if you publish a paper describing a program or a method and everyone uses it, you’re going to get a lot of citations.

There are plenty of people who decry the Impact Factor and say it should be abandoned, mainly along the lines that IF is a poor predictor of an individual article’s number of citations. I find this argument a bit daft, because the e.g. 2012 IF is (roughly) the average number of citations in 2012 to papers published in 2010 and 2011. This ‘poor predictor’ criticism is thus equivalent to slamming the arithmetic mean for failing to predict the variance.

I do agree that the IF of the journal should not be used to judge the value of an individual paper or, in aggregate, the contribution of an individual researcher. Something like the h-index is much more effective, as it give little weight to outliers like the Arlequin paper. Another useful feature of h-indices is that you can apply them to any grouping of articles, such as a journal. For example, ME Resources’ h-index for papers published in 2010 and 2011 is 30, which means that we have 30 papers with 30 or more citations from those years. Our higher 2012 IF is thus due to good citation rate for a large number of papers, and not just lots of citations for one or two.

Molecular Ecology also did well this year, recovering from its fall in 2011 from 6.45 to 5.52 back up to 6.27. I suspect that this is because we didn’t have any special issues in 2009, but had three spread between 2010 and 2011 (see here, here and here). These attract a lot of attention from the community and hence garner plenty of citations in the following years. I’m interested to see what happens next year.

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About Tim Vines

I'm the managing editor of Molecular Ecology and Molecular Ecology Resources.
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  • Erik Svensson

    To me, the journal IF says almost nothing – contrary to what is implicated in this text, as different fields will have different IF:s, irrespective of inherent “quality”. I have published in both ME, MER, Evolution, American Naturalist and other leading journals in ecology and evolution. In spite of their lower IF:s, I personally rank papers in Evolution and American Naturalist much higher than papers in ME and MER, since the former are often more solidly based in theory, whereas the latter journals are more method-driven (which drives up their IF:s). When we are talking about journals at this level (relatively specialized), I do not care so much if IF is 4, 5 or 6, but rather what kind of audience that is reading the articles and their standing in the community of ecologists and evolutionary biologists. To me, and many other ecologists and evolutionists, Am. Nat. and Evolution are the leading journals, and ME and MER are not close to their positions.

    • Tim Vines

      Hi Erik,

      Thanks for your comment. ME Resource’s higher Impact Factor this year does indeed stem from publishing methods and resource papers, which is fine because that’s what the journal is about. Molecular Ecology is almost exclusively empirical papers, and so I don’t think that the difference between ME and Evolution or Am Nat can be attributed to a big difference in the type of paper published. It may be something to do with us publishing more special issues. They’re all good journals.

      I definitely disagree that the IF says ‘almost nothing’, as people clearly pay attention to IF when they decide where to submit. Data on submissions to Mol Ecol in the 12 months after the IF is released shows a decent positive relationship. The best fit line suggests that e.g. a 10% change in IF leads to a 7% change in submissions.

      Tim