If there's one thing that a scientist likes, it's playing with data! To do some quantitative analysis of how publication in chemistry has evolved over the years, I looked at the evolution of JACS articles spanning 5 decades, with statistics on published papers in 1961, 1971, 1981, 1991, 2001 and 2011. So, what can we say?

Average number of authors

JACS authors per paper

The histograms above show the number of authors for a given paper. There is a clear trend towards papers with longer author lists, with the average number of authors increasing from 2.4 (in 1961) to 5.3 (in 2011). Of particular note is the quasi-disappearance of single author papers: while they represented 13.7% of published papers in 1961 (188 out of 1364), there were only 10 in 2011 (out of 3176 papers, i.e. 0.3%).

This is in line with the general idea of modern research being more collaborative, which we can try to confirm by looking at the number of different affiliations per paper (only plotted from 1981 to 2011, as earlier data on affiliation is not available):

JACS affiliations per paper

The average number of affiliations increased from 1.3 to 2.4 over this period, somewhat faster than the increase in authorship. I feel, however, it's important to note there still are large number of single-affiliation papers, which I did not exactly expect (most of my own papers being part of collaborations).

Number of references

Here's the number of references per paper, in 1961, 1991 and 2011:

References per JACS paper

The clear increase in references (average of 18.6 in 1961 vs. 49.1 in 2011) is clear, and is (at least partly) responsible for the background inflation of impact factors, for example. However, it should be noted that the increase has been gradual since 1961, so it cannot be driven by the more recent focus on bibliometrics.


That's it for today, my time is up (rugby's over), but next time I'll focus on the writing of chemistry itself: how the language of titles and abstracts has evolved since 1961… In the meantime, comments on the statistics above or suggestions of additional analyses are very welcome!