PLoS publishes a regular report covering a wide range of metrics covering all of it journals. This is easy to download as a .csv file, from which you can quickly start to create graphical summaries using Excel or STATA. One problem with the way the data is currently presented is that each number represents a cumulative total over time, so causal hypotheses, such as the relationship between citations and downloads are difficult to test.

Many of the metrics included in the report occur fairly infrequently, i.e. there are lots of zeros, and so these variables are probably telling us more about how widespread the use of the different channels is currently, rather than about features of the underlying content. Exceptions include Mendeley, Facebook and Twitter.

Social mediaThe box pots on the right show how the distributions of article references differ by journal (panels A, C & D) and over time (panel B). The three by journal plots use papers published in 2012 as a reference point.  As can be seen in panel B, Mendeley readers continue to add papers for a couple of years where as responses on Twitter and Facebook are more immediate (data not shown).

The Mendeley data generally have a well-defined, non-zero median, whereas Facebook and Twitter are largely made up of outliers – PLoS Medicine is the exception here.

Outlying PLoS ONE articles published 2012 and selected by Mendeley readers tend to be review-like or methods-based…

  • An Study of the Differential Effect of Oxidation on Two Biologically Relevant G-Quadruplexes: Possible Implications in Oncogene Expression
  • Equilibrium of Global Amphibian Species Distributions with Climate
  • Direct Comparisons of Illumina vs. Roche 454 Sequencing Technologies on the Same Microbial Community DNA Sample
  • Double Digest RADseq: An Inexpensive Method for De Novo SNP Discovery and Genotyping in Model and Non-Model Species

…whereas articles frequently posted on Facebook or tweeted seem to have a more popularist appeal:

  • The Power of Kawaii: Viewing Cute Images Promotes a Careful Behavior and Narrows Attentional Focus
  • The Eyes Don’t Have It: Lie Detection and Neuro-Linguistic Programming
  • Lesula: A New Species of Cercopithecus Monkey Endemic to the Democratic Republic of Congo and Implications for Conservation of Congo’s Central Basin
  • Why Most Biomedical Findings Echoed by Newspapers Turn Out to be False: The Case of Attention Deficit Hyperactivity Disorder

Associations between these different metrics require more analysis once the data can be analysed as a times series, but there do appear to be some interesting relationships between citation rates and Mendeley readership numbers.