Of Course Immediate OA Generates More Citations Than Delayed Access

[Stevan Harnad]

Laakso & Björk (2013)<http://hanken.halvi.helsinki.fi/portal/files/1311951/laakso_bj_rk_delay_preprint.pdf>
compare
the citation impact of immediate Gold OA with delayed Gold and toll-access.
They find that delayed-Gold journals average twice as many citations per
article as toll-access journals and three times as many as immediate-Gold
journals.

This is based on comparisons between different journals. But journals
differ in both subject matter and quality -- and one of the ways to try to
equate them to make them comparable for quality is to equate them for
impact.

So if journals are not equated for subject matter and quality, one is
comparing apples and oranges. But if immediate Gold OA, delayed-Gold and
toll-access journals are equated for impact, one can't compare impact for
delayed vs. immediate Gold -- in fact one can't compare the journals for
citation impact at al!!

A feasible way to compare immediate-OA with delayed-access and toll-access
is via Green OA based on within-journal instead of between-journal
comparisons, by comparing articles published within the same journal and
year. To do this one needs both the date of publication and the date the
article was made Green OA.

It is impossible to get the OA date for webwide deposits in general, but
for repository deposits it is possible.

We do have some very preliminary and partial
data<http://eprints.soton.ac.uk/358882/> from
the University of Minho repository, but the sample is still too small to do
within-journal comparisons. Immediate Green OA articles do have more
citations on average than Delayed Access articles (see Figures 2c and 3c)
despite the availability of the automated "Almost-OA" Button during the
delay period, but these citation counts are just absolute ones, rather than
relative to within-journal matched toll-access controls. Hence these are
likewise still comparisons between apples and oranges. (Note also that the
large number of undeposited articles is likewise unmatched, and not based
on their respective within-journal matched toll-access controls.)

The sample will grow as the number of Green OA mandates and repository
deposits worldwide grows. The vast unused potential for immediate Green-OA
and Almost-OA has long been known and noted -- most recently by Laakso
(2014)<http://hanken.halvi.helsinki.fi/portal/files/2323707/Lakso_2014_Green_OA_Policies_Accepted_Version_.pdf>
.

Gargouri, Yassine, Larivière, Vincent & Harnad, Stevan (2013) Ten-year
Analysis of University of Minho Green OA Self-Archiving
Mandate<http://eprints.soton.ac.uk/358882/> (in
E Rodrigues, Ed. *title to come)*

Laakso, M., & Björk, B. C. (2013). Delayed open access: An overlooked
high-impact category of openly available scientific
literature<http://hanken.halvi.helsinki.fi/portal/files/1311951/laakso_bj_rk_delay_preprint.pdf>
. *Journal of the American Society for Information Science and Technology*.

Laakso, M (2014) Green open access policies of scholarly journal
publishers: a study of what, when, and where self-archiving is
allowed<http://hanken.halvi.helsinki.fi/portal/files/2323707/Lakso_2014_Green_OA_Policies_Accepted_Version_.pdf>.
Scientometrics (in press)
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