Since 2005, I have been tracking a number of data to determine a
reasonable estimate of the extent and rate of growth of open access,
on a quarterly basis. It is difficult to determine accurate macro-
level data; this discussion and the work of other researchers is much
appreciated.
DOAJ has grown from 1,400 journals in 2005 to over 4,500 today. This
is an imperfect measure, but sufficient to illustrate the dramatic
growth in number of journals. Net DOAJ growth for 2009 was 723 titles,
approximately 2 titles per day. About a third of DOAJ journals are
searchable at article level; the number of articles available through
such a search showed a 33% growth in 2009, to over 300,000 items.
DOAJ does not include journals with free back issues, or gold OA
articles in hybrid journals, so DOAJ numbers are an underestimate of
gold OA.
The number of documents available through the broadest cross-
repository search engines grew from about 5 million in 2005 (based on
OAIster statistics) to over 22 million in 2009 (based on BASE stats).
These, too, are imperfect figures as not all items in repositories are
full-text research articles, and there is likely some duplication,
however even allowing for these imperfections the very strong growth
rate is clear.
The percentage of medical research literature published in the last 3
years and indexed in PubMed that is freely available is 20% (very
similar to Bjork's figure). This is based on a search of PubMed, and
does not distinguish between gold and green OA.
For data showing 2009 growth, see:
http://spreadsheets.google.com/ccc?key=0Apn66wofwO7adF93d1lIS1VCVHhnZ0pTemVFX1hTT0E&hl=en
The full series, including links to all open data versions and
commentary, can be found at:
http://poeticeconomics.blogspot.com/2006/08/dramatic-growth-of-open-access-series.html
Heather Morrison
The Imaginary Journal of Poetic Economics
http://poeticeconomics.blogspot.com
Received on Mon Jan 11 2010 - 22:38:05 GMT