Fwd: Mandated and Unmandated Open Access: Comparing Green and Gold

[Stevan Harnad <amsciforum@gmail.com>]

--------- Forwarded message ----------
From: Yassine Gargouri  yassinegargouri -- hotmail.com
Date: Sat, Aug 28, 2010 at 2:27 PM
To: SIGMETRICS -- listserv.utk.edu

Jan Velterop has posted his hunch that of the overall percentage 
of articles published annually today most will prove to be 
articles in Gold OA journals, once one separates from the 
articles classified as self-archived Green OA those self-archived 
articles that are also published in Gold OA journals:

"Is anyone aware of credible research that shows how many 
articles (in the last 5 years, say), outside physics and the 
Arxiv preprint servers, have been made available with OA 
exclusively via 'green' archiving in repositories, and how many 
were made available with OA directly ('gold') by the publishers 
(author-side paid or not)?
"The 'gold' OA ones may of course also be available in 
repositories, but shouldn't be counted for this purpose, as their 
OA status is not due to them being 'green'.
"It is my hunch (to be verified or falsified) that publishers 
(the 'gold' road) have actually done more to bring OA about than 
repositories, even where mandated (the 'green' road)."
--J. Velterop, American Scientist Open Access Forum, 25 August 
2010
--http://bit.ly/VelteropHunch

The results turn out to go strongly contrary to Velterop's 
hypothesis.

Our ongoing project is comparing citation counts for mandated 
Green OA articles with those for non-mandated Green OA articles, 
all published in journals indexed by the Thompson/Reuters ISI 
database (science and social-science/humanities). (We use only 
the ISI-indexed sample because the citation counts for our 
comparisons between OA and non-OA are all derived from ISI.)

The four mandated institutions were Southampton University (ECS), 
Minho, Queensland and CERN.

Out of our total set of 11,801 mandated, self-archived OA 
articles, we first set aside all those (279) articles that had 
been published in Gold OA journals (i.e., the journals in the 
DOAJ-indexed subset of ISI-indexed journals) because we were 
primarily interested in testing the OA citation advantage, which 
is based on comparing the citation counts of OA articles versus 
non-OA articles published in the same journal and year. (This can 
only be done in non-OA journals, because OA journals have no 
non-OA articles.) This left only the Green OA articles published 
in non-Gold journals.

We then extracted, as control articles for this purely Green OA 
subset, 10 keyword-matched articles published in the same journal 
and year. The total number of articles in this control sample for 
the years 2002-2008 was 41,755 (our preprint for PloS, Gargouri 
et al. 2010, covers a somewhat smaller, earlier period: 
2002-2006, with 20,982 control articles).

Next we used a robot to check what percentage of these control 
articles was OA (freely accessible on the web).

Of our total set of 11,801 mandated, self-archived articles, 279 
articles (2.4%) had been published in the 63 Gold OA journals 
(2.6%) among the 2,391 journals in which the authors from our 
four mandated institutions had published in 2002-2008. Both these 
estimates of percent Gold OA are about half as big as the total 
5% proportion for Gold OA journals among all ISI-indexed journals 
(active in the past 10 years). ?To be conservative, we can use 
the higher figure of 5% as a first estimate of the Gold OA 
contribution to total OA among all ISI-indexed journals.

Now, in our sample, we find that out of the total number of 
articles published in ISI-indexed journals by authors from our 
four mandated institutions between 2002-2008 (11,801 articles), 
about 65.6% of them (7,736 articles) had indeed been made Green 
OA through self-archiving by their authors, as mandated (7,457 or 
63.2% Green only, and 279 or 2.4% both Green and Gold).

In contrast, for our 42,395 keyword-matched, non-mandated control 
articles, the percentage OA ?was 23.4% (21.9% Green and 1.5% 
Gold).

Bjork's et al's (2010) corresponding figures for his ISI sample 
(1282 articles for 2008 alone, calculated in 2009), was 20.6% OA 
(14% Green, 6.6% Gold).

The variance is probably due to discipline blends in the samples, 
but whichever sample and figures one chooses ? whether our 21.9% 
Green and 1.5% Gold or Bjork's et al?s 14% Gold and 6.6% Green, 
the figures fail to bear out Verlterop?s prediction that:

"publishers (the 'gold' road) have actually done more to bring OA 
about than repositories, even where mandated (the 'green' road)."
--http://bit.ly/VelteropHunch

Moreover (and this is really the most important point of all), 
the hunch is the wrongest of all precisely for where OA is 
mandated, for there the percent Green is over 60%, and headed 
toward 100%. That is the real power of Green OA mandates.

Yassine Gargouri

Gargouri, Y., Hajjem, C., Lariviere, V., Gingras, Y., Brody, T., 
Carr, L. and Harnad, S. (2010) Self-Selected or Mandated, Open 
Access Increases Citation Impact for Higher Quality Research. 
PLOS ONE (under review)
http://eprints.ecs.soton.ac.uk/18493/

Bjork B-C, Welling P, Laakso M, Majlender P, Hedlund T, et al. 
(2010) Open Access to the Scientific Journal Literature: 
Situation 2009. PLOS ONE 5(6): e11273. 
http://dx.plos.org/10.1371/journal.pone.0011273 .