It is a sign of the maturity of open access that good, reliable figures are available. The latest stats from OASPA, the Open Access Scholarly Publishers Assocation, reveal that there were 160,995 open-access articles published in 2015. What do they mean by OA? OASPA counts those arcitles that are published with a CC-BY licence. This excludes several commercial publishers who publish open-access but with some limitations (an interesting detail that emerged very clearly from recent open-access conference in Cambridge, which I reported here). OASPA list 52 publishers responsible for these articles, ranging from the vast (Springer Nature, PLOS) to the tiny, with only one or two journals, such as the Military Technical Courier published by the Serbian Ministry of Defence. They also report on the large number of publishers who have not been accepted for inclusion in their association.
They plot the growth of OA journal article publishing over the last fifteen years, and for comparison, I have added the number of OA books published – a rather different story. The number of open-access books has have also increased, but by a much gentler curve. And at the slower rate they are growing, they will never approach the number of journals published:
Crucially, there seems to be no agreement over a single CC licence for books. The agreements for books seem to be split by the various licence types. This suggests a very different situation for publishing open-access books compared with open-access journals. The lack of agreement can be seen clearly in this pie chart:
Why is the situation so different for books compared to journals? That is a topic for another post; of course there are fewer books than articles, but it is not as simple as that. Suffice it to say that based on current trends there is no likelihood that open-access books will become as widespread as open-access journal articles.