Saturday, August 24, 2013

The most desirable citations

Not all citations are equal.
This highlights how they are an imperfect measure of scientific impact.
Broadly they might be classified as being of two types.

1. Token.
"There are many papers on this topic, including Jones et al."

2. Substantial.
"We use the results [method, equation, material, or concept] of Jones et al. to obtain new results".

There is a big difference. For token citations, the existence of the citing paper is really independent of the cited paper, i.e., it would not really matter whether or not the cited paper existed.
In contrast, for substantial citations,  parts [or even the whole] of the citing paper would not exist if the cited paper did not exist.

Unfortunately, too many of the citations I receive are token rather than substantial. I find this discouraging and embarrassing. Even worse, a few times I have been cited as "McKenzie has shown X to be true" when my paper actually showed X to be false!

Thus, it is very satisfying when someone actually uses your results in a constructive manner.
Recently, Tony Wright and I published a paper Quantum oscillations and Berry's phase in topological insulator surface states with broken particle-hole symmetry. One of our results was to propose a method to more robustly extract a signature of the Berry's phase from experimental data.

Tony pointed out to me a recent preprint that actually uses our method (see the Figure below).

The preprint is by a Korean Rugby League team [13 players]

Spin-Chiral Bulk Fermi Surfaces of BiTeI Proven by Quantum Oscillations
Joonbum Park, E. Kampert, Kyung-Hwan Jin, Man Jin Eom, Jongmok Ok, E.S. Choi, F. Wolff-Fabris, K.D. Lee, N. Hur, J.-S Rhyee, Y.J. Jo, Seung-Hoon Jhi, and Jun Sung Kim


  1. There is a third type of citation that I find useful: one that places your work into a helpful spot in the "web" of science citations.

    For example, I work on the LAO/STO interface. The seminal paper on this interface was published in 2004. Since then, some of its claims have been proven wrong, so I wouldn't refer someone to this paper to learn about the LAO/STO interface. Nonetheless, I think it's still worthwhile to cite this seminal paper because it helps your paper fit properly into the web of science citations. By citing the seminal paper, you are saying that your paper follows from it and giving an easy way for your audience to find your paper. The main way that find new papers in the field is by searching for papers that cite this seminal paper. In this case, the citation serves a sort of meta purpose - I'm not citing the paper to refer readers to it, or to acknowledge some method that I copied, but rather to help readers find my paper and understand where it fits into the grand web of science.

  2. Oops, "The main way that find new papers" should be "The main way that I find new papers"

  3. I have recently started getting many more substantial/essential citations. Unfortunately, I am quite certain that hiring committees don't make this distinction.

    1. I think that hiring and tenure committees at the best institutions do make this distinction.

      Mediocre institutions are run by bean counters and do not make such distinctions.

  4. An additional nice element of the Korean "rugby team" paper you mentioned is that all the authors have different last names. This is not so easy to achieve in a country with a highly asymmetric distribution of family names:

    1. David, thanks for the interesting observation.

  5. I had the (whimsical) idea of weighting citations from the middle of a paper more than those from the introduction and conclusion. In this way citations of the form "Now we use the method of Ref. [...]" count for more than the kind you call token, which are more a reflection of the social connections of the authors.