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.