I noticed something strange about the 2013 Impact Factor data for eLife.
Before I get onto the problem. I feel I need to point out that I dislike Impact Factors and think that their influence on science is corrosive. I am a DORA signatory and I try to uphold those principles. I admit that, in the past, I used to check the new Impact Factors when they were released, but no longer. This year, when the 2013 Impact Factors came out I didn’t bother to log on to take a look. A chance Twitter conversation with Manuel Théry (@ManuelTHERY) and Christophe Leterrier (@christlet) was my first encounter with the new numbers.
Huh? eLife has an Impact Factor?
For those that don’t know, the 2013 Impact Factor is worked out by counting the total number of 2013 cites to articles in a given journal that were published in 2011 and 2012. This number is divided by the number of “citable items” in that journal in 2011 and 2012.
Now, eLife launched in October 2012. So it seems unfair that it gets an Impact Factor since it only published papers for 12.5% of the window under scrutiny. Is this normal?
I looked up the 2013 Impact Factor for Biology Open, a Company of Biologists journal that launched in January 2012* and… it doesn’t have one! So why does eLife get an Impact Factor but Biology Open doesn’t?**
Looking at the numbers for eLife revealed that there were 230 citations in 2013 to eLife papers in 2011 and 2012. One of which was a mis-citation to an article in 2011. This article does not exist (the next column shows that there were no articles in 2011). My guess is that Thomson Reuters view this as the journal existing for 2011 and 2012, and therefore deserving of an Impact Factor. Presumably there are no mis-cites in the Biology Open record and it will only get an Impact Factor next year. Doesn’t this call into question the veracity of the database? I have found other errors in records previously (see here). I also find it difficult to believe that no-one checked this particular record given the profile of eLife.
Perhaps unsurprisingly, I couldn’t track down the rogue citation. I did look at the cites to eLife articles from all years in Web of Science, the Thomson Reuters database (which again showed that eLife only started publishing in Oct 2012). As described before there are spurious citations in the database. Josh Kaplan’s eLife paper on UNC13/Tomosyn managed to rack up 5 citations in 2004, some 9 years before it was published (in 2013)! This was along with nine other papers that somehow managed to be cited in 2004 before they were published. It’s concerning enough that these data are used for hiring, firing and funding decisions, but if the data are incomplete or incorrect this is even worse.
Summary: I’m sure the Impact Factor of eLife will rise as soon as it has a full window for measurement. This would actually be 2016 when the 2015 Impact Factors are released. The journal has made it clear in past editorials (and here) that it is not interested in an Impact Factor and won’t promote one if it is awarded. So, this issue makes no difference to the journal. I guess the moral of the story is: don’t take the Impact Factor at face value. But then we all knew that already. Didn’t we?
* For clarity, I should declare that we have published papers in eLife and Biology Open this year.
** The only other reason I can think of is that eLife was listed on PubMed right away, while Biology Open had to wait. This caused some controversy at the time. I can’t see why a PubMed listing should affect Impact Factor. Anyhow, I noticed that Biology Open got listed in PubMed by October 2012, so in the end it is comparable to eLife.
Edit: There is an update to this post here.
Edit 2: This post is the most popular on Quantixed. A screenshot of visitors’ search engine queries (Nov 2014)…
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The post title is taken from “Strange Things” from Big Black’s Atomizer LP released in 1986.