Citation Vacuums

In science, there’s a simple currency earned by important publications: citations by subsequent papers. Each citation gives credit, a small nod of recognition, a karma point, a feather in the cap. We are proud when our publications garner many citations. Citation count, however, is not a great metric of true quality or impact: all that glitters is not gold; all that is gold does not glitter. Counting citations sometimes credits authors with a greater part in advancing the field than they deserve, and fails to credit those who do.

I remember many years ago hearing David Swofford, the author of the widely-used PAUP program for analyzing evolutionary trees, grumbling about a paper just published. His complaint was that the paper’s “novel” concept wasn’t particularly novel — it was so obviously implicit in the literature’s ideas that none among the most theoretically astute biologists thought it was worth publishing in a standalone paper. And yet, the paper was published, and received attention precisely because no other paper had previously said that useful (though obvious) idea so directly.

Such gap in the literature is a “citation vacuum“, a region of “idea space” that is well within the current paradigm, but unoccupied by a citable paper. Over the years I’ve seen several vacuums exploited to the career benefit of their discoverers. We scientists like to cite compact, precise, and strong statements of an idea, and if none exists, then there is a vacuum in the literature waiting to be filled. It doesn’t matter if the idea is already understood by many, or if the idea is in fact already in the literature but in a long-forgotten paper or buried on page 9 of a software manual. It only matters that there is no obvious paper to cite, and if you write one, cha-ching, the citations come rolling in.

I’m reluctant to name names. Most authors who’ve written vacuum-filling papers probably don’t think of them as such, instead believing them highly novel, and I wouldn’t want to disturb their glory. I will mention one name, however — my own. My best cited paper is my 1997 paper “Gene Trees in Species Trees”. When I wrote it, I didn’t think of it cynically as a vacuum-filler, but in many ways, that’s what it was. It was a condensation of the Zeitgeist, gathering together and organizing ideas that probably were already, in large part, in the heads of the leaders of the field. It’s become a magnet for citations because it’s accessible and provides a compact citation for the field’s perspective. It’s a pedagogically useful paper, but I expect that it brought the median understanding in the field forward more than it informed those at the cutting edge.

So, go find a vacuum, publish, and profit*.

*To be clear: I’m not advocating that you withhold credit to your predecessors. Please, when filling a vacuum, look for and cite the papers that set up (or perhaps even mention) your idea. Treat your paper as a new attempt to synthesize and explain ideas already in the conversation of the field. Take credit for the clarity and thoroughness of your exposition, because those may be new, and will add value to the field.

3 thoughts on “Citation Vacuums

  1. This was a great paper. It alerted me, and maybe many others, to the truth of what a “phylogeny” consists of. Yes, maybe others thought the same thoughts, but your paper encapsulated what needed to be said, and I hadn’t read any of the earlier, more confusing papers on this topic. Before this, we all thought that species evolved in simple trees, and we could use any locus to show what the true tree was! Imagine!

    In retrospect, your paper didn’t recognize that there might be an “anomaly zone,” — a later discovery. So the average of the gene trees is not necessarily going to give you the species tree, even without reticulation. Lately, we’ve realized that the species tree might be even more divergent from the gene tree than even under the simple multispecies coalescent, because of introgression. And introgression is much more common than we thought it was back then.

    But reading your paper woke me, at least, to the ideas that form the basis of those I now espouse. It was a prophetic and important paper, and I’d have been much prouder than you apparently are if it were me that had written it.

  2. Pingback: Recommended reads #121 | Small Pond Science

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