In "Next-Generation Implications of Open Access,"
     http://www.ctwatch.org/quarterly/print.php?p=80
in the August CTWatch
     http://www.ctwatch.org/quarterly/articles/2007/08/
Paul Ginsparg wrote:

>   Studies have shown a correlation between openly accessible materials
>   and citation impact, though a direct causal link is more difficult
>   to establish, and other mechanisms accounting for the effect are
>   easily imagined.

The causal mechanisms underlying the positive correlation between OA
and research impact are not only imaginable, but the five most probable
causal contributors have already been repeatedly itemized:
     http://users.ecs.soton.ac.uk/harnad/Hypermail/Amsci/4757.html
Indeed, they were listed in another article in the same CTWatch issue
"Incentivizing the Open Access Research Web"
     http://www.ctwatch.org/quarterly/print.php?p=86

     OA Advantage (OAA) = EA + QA + UA + (CA) + (QB)

     EA: Early Advantage: Self-archiving preprints before publication
     increases citations (higher-quality articles benefit more)

     QA: Quality Advantage: Self-archiving postprints upon publication
     increases citations (higher-quality articles benefit more)

     UA: Usage Advantage: Self-archiving increases downloads
     (higher-quality articles benefit more)

     (CA: Competitive Advantage): OA/non-OA advantage (CA disappears
     at 100% OA)

     (QB: Quality Bias): Higher-quality articles are self-selectively
     self-archived more (QB disappears at 100% OA)

>   It is worthwhile to note, however, that even if some articles
>   currently receive more citations by virtue of being open access,
>   it doesn't follow that the benefit would continue to accrue through
>   widespread expansion of open access publication.

Worthwhile to note, and already noted (see above). However, the
"widespread expansion to open access" has *not* yet taken place, and
that's the point! The urgent and substantive item on the agenda concerns
*how* to make it take place. And the competitive advantage is one of
those incentives. (So  are EA, QA, and UA.)

(Note also that the objective of OA is OA, not necessarily or primarily
OA *publication*, which is Gold OA. 100% OA can be achieved via Green OA
self-archiving of non-OA publications, and that is what OA mandates by
research funders and universities are aiming for. Green OA is entirely
in the hands of the research community, and can be accelerated and
ensured through Green OA mandates. Gold OA is largely in the hands of
publishers, cannot be mandated, and can and will take care of itself,
if need be, *after* OA itself has been achieved, through Green OA.)

>   Indeed, once the bulk of publication is moved to open access, then
>   whatever relative boost might be enjoyed by early adopters would
>   long since have disappeared, with relative numbers of citations once
>   again determined by the usual independent mechanisms.

About 90% of citations are accorded to about 10% of articles. Roughly
speaking, this means that the most useful articles are used most, and
that they are approximately the top 10%. It is also the most useful
articles that benefit from OA the most. The correlation is between
citation counts and probability of being OA: OA does not help weak
articles get cited more, though it can unearth occasional gems that
are published in obscure and little-subscribed-to journals.

It is also true that the top 10% of articles are more likely to be
published in the top 10% of journals, which are also the most widely
subscribed-to -- hence the most accessible -- journals. But even so,
they are not accessible to all their potential users, because most
universities can only afford to subscribe to a small fraction of journals.

Hence, even after all research is OA, and the competitive advantage is
all gone, the distribution of usage and citations will not simply be
"once again determined by the usual independent mechanisms." There will
now be a level playing field, with article quality and usefulness (QA, UA)
the only determinants of what is used and cited, not journal affordability
and accessibility. And the beneficiary will be the entire research cycle,
its productivity and its progress.

>   Citation impact per se is consequently not a serious argument for
>   encouraging more authors to adopt open access publication.

Not only is impact enhancement a serious argument to authors for providing
OA (not necessarily Gold OA publication!) to their published articles,
but it is the strongest argument for OA: Either OA does increase
research usage, hence its productivity and progress, or it doesn't. If
it doesn't, there is little remaining rationale for OA: Teaching? Maybe,
but how much of primary research output will ever be used and useful for
teaching? Public access? For things like health-relevant findings, yes,
but how much of primary research output will ever be used or useful for
public reading?

>   A different potential impact and benefit to the general public, on
>   the other hand, is the greater ease with which science journalists
>   and bloggers can write about and link to open access articles.

If the primary rationale for OA were accessibility to science journalists,
the OA movement would be dead in the water. Instead of making the annual
2.5 million articles in 25,000 journals across all disciplines and
languages OA, publishers could simply agree to the compromise of making
their online sites freely accessible to designated journalists. End
of story. No need for IRs, no need for self-archiving, no need for Green
OA mandates (and of course no need for Gold OA publication).

As to bloggers: As with everything else, most of what they blog is not of
interest to most. The important bloggings about research will come from
researchers themselves, and will simply be part of the Early Advantage
(EA) of OA, which is yet another contributor to the OA usage/impact
advantage, the primary "serious" and scalable rationale for OA.

Stevan Harnad
AMERICAN SCIENTIST OPEN ACCESS FORUM:
http://amsci-forum.amsci.org/archives/American-Scientist-Open-Access-Forum.html
     http://www.ecs.soton.ac.uk/~harnad/Hypermail/Amsci/

UNIVERSITIES and RESEARCH FUNDERS:
If you have adopted or plan to adopt an policy of providing Open Access
to your own research article output, please describe your policy at:
     http://www.eprints.org/signup/sign.php
     http://openaccess.eprints.org/index.php?/archives/71-guid.html
     http://openaccess.eprints.org/index.php?/archives/136-guid.html

OPEN-ACCESS-PROVISION POLICY:
     BOAI-1 ("Green"): Publish your article in a suitable toll-access journal
     http://romeo.eprints.org/
OR
     BOAI-2 ("Gold"): Publish your article in an open-access journal if/when
     a suitable one exists.
     http://www.doaj.org/
AND
     in BOTH cases self-archive a supplementary version of your article
     in your own institutional repository.
     http://www.eprints.org/self-faq/
     http://archives.eprints.org/
     http://openaccess.eprints.org/