One of the things to look for when doing citation searches is self-citations. If Joe Bloggs’s 1999 masterpiece has lots of citations, but it turns out that’s only because Bloggs has been citing Bloggs 1999 in everything he writes, then it isn’t clear that citation counts are measuring impact correctly. For that reason, many measures of citation exclude self-citation by authors. There are complications with this, especially with co-authored pieces. (If a paper by Stanley and Williamson cites Stanley and Szabo 2000, is that a self-cite? Should it be, given the rationale for excluding self-cites?) But overall I think it gives a better measure of citation impact.
We can ask the same question about journals. How much is the work in journal X being cited overall is a different question from how much it is being cited elsewhere. To get a sense of how big an issue this is, we can look at how frequently the journals publish articles citing other articles in that very journal. And that’s what I did. The table below counts how many articles in each of the big 3 journals cite articles published in the big 3 journals from 2000 to the present.
A few caveats before the table. I’ve taken this from Web of Knowledge, because I couldn’t figure out how to do the same thing with Google Scholar. I haven’t included Nous, partially because I’m lazy, and partially because of technical challenges. Perhaps most importantly, Web of Knowledge includes book reviews in Mind as articles, but not book reviews in Philosophical Review. That means the raw number of articles in Mind is much greater than in the other 2. (Roughly 600 articles in Mind, versus under 200 in Philosophical Review, and 350 in Journal of Philosophy.) That said, here’s the table.
As you can see, journals cite themselves a lot. The huge number in the middle in part reflects Mind’s love of discussion notes, replies to discussion notes, and so on. (And in part reflects the odd fact that book reviews in Mind are counted in Web of Knowledge.) But don’t let that distract you too much; every journal is like this to some degree.
Of course, this is what you’d expect if the journals specialised. If article authors think that discussions about conceivability and possibility go to Philosophical Review, about conditionals go to Mind, and about the nature of function go to Journal of Philosophy, and they think that on the excellent ground that that’s where such articles in the past have gone, then of course those articles will end up citing largely other articles from the same journal. (This fact, that people send articles on X to places that have recently published on X, I think explains the bulk of the data.)
It’s also what you’d expect if either (a) editors demanded that authors recognise their perceptiveness in what they had previously chosen to publish by citing it well, or (b) authors believed that editors demanded this, whether or not they do.
And it’s also what you’d expect if editors of journal X were aware that a paper previously published in X was relevant to some new article, and properly insisted on it being cited, while they were not as aware of (or not as insistent about) relevant literature in journals X and Y.
Figuring out which of these three explanations – or others – is correct is for another time. I just wanted to note the data.
One last point. I started to do this because I’d been asked whether the odd data in the previous post (about the Journal not citing some classic papers in recent philosophical semantics) was part of a broader trend of the Journal not citing recent literature as much as the other top journals do. I don’t think this data alone either confirms or disconfirms that hypothesis. It’s true that the Journal cites the other top 2 journals at a lower rate than either Mind or Phil Review cite the other top 2 journals. But it’s not by much, and this could be a consequence of the Journal having (either because of editorial policy or submission patterns by authors) a different range of topics than the other top 2.