I recently posed to this list the question âHow many researchers are there in the world?â and gave some rough estimates that bounded the result N by 1M < N < 10M. I have received several very useful pieces of data (and some non-useful responses). The question is clearly relevant to the production rate of articles.
 My best estimate of N is now 3.60M researchers in 2012. This is based on the UNESCO Science Report 2010 which details researchers by country, and this is an extrapolation from 2 354 851 in 2002 and 2 979 913 in 2007. Note: This figure is to be treated with caution, because of the following factors: 1.     I use the FTE counts which are higher than the headcounts. On inspection, many countries (such as Canada, USA and Australia) did not supply UNESCO with headcounts. I could have fudged the two categories together but the precision of the data did not seem to warrant that. 2.     The raw data is itself subject to various errors. The footnote to the Table states âText Box: â Text Box: â Text Box: â Text Box: â Text Box: â ân/+n = data refer to n years before or after reference year; a = university graduates instead of researchers; b = break in series with previous year for which data are shown; e = estimation; g = underestimated or partial data; h = overestimated or based on overestimated data.â 3.     Not all of these researchers are what I call âproducing researchersâ: researchers who (co)author articles which could be made open access. It is difficult to determine this factor though use of article-based author-lists or author IDs may be useful. This is probably the biggest uncertainty in the data, and means that 3.60M is probably an over-estimate.  One of the reasons I wanted to know this value is to see how large the Mendeley count of users is â they report 1.43M at time of writing. Some of these are not âproducing researchersâ, but are people searching literature for work, hobby or medical purposes, but private communication suggests this is a relatively small fraction of the total. In any case, just to do the raw numbers: 1.4M / 3.60M = 40%. If point 3 above dominates, this is an under-estimate of Mendeleyâs penetration as a researcher tool.  What this implies is that 40% (or whatever) of researchers in the world are using Mendeley, and have the potential to make their work open access by simple actions. Les Carr has blogged that the level of people doing this is about the same as the level achieved in his University of Southampton departmental mandated repository. Thatâs good news in itself. However, it now poses a new set of questions: are the researchers in Mendeley different from those represented in institutional repositories, the same ones, or what is the overlap? Surely this will vary by discipline?  If the user sets their own works to be OA, and the users are disjoint from repository users, then that implies that the Titanium Road (social networking OA) is making significant progress in the OA campaign in its own right, and growing at about 37% from June 2011 to January 2012. The complementary approach to institutional repositories may be valuable.  [IMAGE]  The same question may be asked of articles, but it is more difficult to draw conclusions. An article may be put into a repository and made OA by one co-author, and into Mendeley and made OA by another. I argue this is a net benefit - the more copies of an article on the Internet the better (within reason) though not as useful as a new article made OA. Some however may simply be focussed solely on different article counts and think of this as a waste of effort. No matter â it seems that social networking tools are proving useful in achieving OA.  Arthur Sale University of Tasmania, Australia  [ Part 1.2, Image/PNG (Name: "image001.png") 189 bytes. ] [ Unable to print this part. ] [ Part 1.3, Image/PNG (Name: "image002.png") 186 bytes. ] [ Unable to print this part. ] [ Part 1.4, Image/PNG (Name: "image003.png") 186 bytes. ] [ Unable to print this part. ] [ Part 1.5, Image/PNG (Name: "image006.png") 21 KB. ] [ Unable to print this part. ] [ Part 2: "Attached Text" ] _______________________________________________ GOAL mailing list GOAL@eprints.org http://mailman.ecs.soton.ac.uk/mailman/listinfo/goal