Wait, HOW is the JIF calculated?

April 29, 2019

I still don’t understand the calculation of Journal Impact Factor. Or, I didn’t until today. Not completely. I mean, yes, I had the basic idea that it was citations divided by the number of citable articles published in the past two years. However, when I write blog posts talking about how you should evaluate your own articles in the context (e.g., this one), I didn’t get it quite right. The definition from the source:

the impact factor of a journal is calculated by dividing the number of current year citations to the source items published in that journal during the previous two years

So when we assess how our own article contributes to the journal impact factor of the journal it was published in, we need to look at citations in the second and third calendar years. It will never count the first calendar year of publication, somewhat getting around the question of whether something has been available to be seen and cited for a full calendar year before it “counts” for JIF purposes. So when I wrote:

The fun game is to take a look at the articles that you’ve had rejected at a given journal (particularly when rejection was on impact grounds) but subsequently published elsewhere. You can take your citations in the “JCR” (aka second) year of the two years after it was published and match that up with the citation distribution of the journal that originally rejected your work. In the past, if you met the JIF number, you could be satisfied they blew it and that your article indeed had impact worthy of their journal. Now you can take it a step farther because you can get a better idea of when your article beat the median. Even if your actual citations are below the JIF of the journal that rejected you, your article may have been one that would have boosted their JIF by beating the median.

I don’t think I fully appreciated that you can look at citations in the second and third year and totally ignore the first year of citations. Look at the second and third calendar year of citations, individually, or average them together as a short cut. Either way, if you want to know if your paper is boosting the JIF of the journal, those are the citations to focus on. Certainly in my mind when I do the below mentioned analysis I used to think I had to look at the first year and sort of grumble to myself about how it wasn’t fair, it was published in the second half of the year, etc. And the second year “really counted”. Well, I was actually closer with my prior excuse making than I realized. You look at the second and third years.

Obviously this also applies to the axe grinding part of your analysis of your papers. I was speaking with two colleagues recently, different details but basically it boils down to being a little down in the dumps about academic disrespect. As you know Dear Reader one of the things that I detest most about the way academic science behaves is the constant assault on our belongingness. There are many forces that try to tell you that you suck and your science is useless and you don’t really deserve to have a long and funded career doing science. The much discussed Imposter Syndrome arises from this and is accelerated by it. I like to fight back against that, and give you tools to understand that the criticisms are nonsense. One of these forces is that of journal Impact Factor and the struggle to get your manuscripts accepted in higher and higher JIF venues.

If you are anything like me you may have a journal or two that is seemingly interested in publishing the kind of work you do, but for some reason you juuuuuust miss the threshold for easy acceptance. Leading to frequent rejection. In my case it is invariably over perceived impact with a side helping of “lacks mechanism”. Now these just-miss kinds of journals have to be within the conceivable space to justify getting analytical about it. I’m not talking about stretching way above your usual paygrade. In our case we get things in this one particular journal occasionally. More importantly, there are other people who get stuff accepted that is not clearly different than ours on these key dimensions on which ours are rejected. So I am pretty confident it is a journal that should seriously consider our submissions (and to their credit our almost inevitably do go out for review).

This has been going on for quite some time and I have a pretty decent sample of our manuscripts that have been rejected at this journal, published elsewhere essentially unchanged (beyond the minor revisions type of detail) and have had time to accumulate the first three years of citations. This journal is seriously missing the JIF boat on many of our submissions. The best one beat their JIF by a factor of 4-5 at times and has settled into a sustained citation rate of about double theirs. It was published in a journal with a JIF about 2/3rd as high. I have numerous other examples of manuscripts rejected over “impact” grounds that at least met that journal’s JIF and in most cases ran 1.5-3x the JIF in the critical second and third calendar years after publication.

Fascinatingly, a couple of the articles that were accepted by this journal are kind of under-performing considering their conceits, our usual for the type of work etc.

The point of this axe grinding is to encourage you to take a similar quantitative look at your own work if you should happen to be feeling down in the dumps after another insult directed at you by the system. This is not for external bragging, nobody gives a crap about the behind-the-curtain reality of JIF, h-index and the like. You aren’t going to convince anyone that your work is better just because it outpoints the JIF of a journal it didn’t get published in. Editors at these journals are going to continue to wring their hands about their JIF, refuse to face the facts that their conceits about what “belongs” and “is high impact” in their journal are flawed and continue to reject your papers that would help their JIF at the same rate. It’s not about that.

This is about your internal dialogue and your Imposter Syndrome. If this helps, use it.

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