Re: Open Access Speeds Use by Others

[Stevan Harnad <harnad@ecs.soton.ac.uk>]

On Tue, 16 May 2006, Chuck Hamacker wrote:

> Chronicle of Higher Education
> http://chronicle.com/news/article/438/open-access-speeds-use-by-others-of-scientific-papers-study-finds
>
> http://biology.plosjournals.org/perlserv/?request=3Dget-document&doi=3D10=.1371/journal.pbio.0040157

I've sent the following letter to CHE:

     The Eysenbach study is certainly not "the first to compare open-access
     and non-open-access papers from the same journal." See the growing
     bibliography of studies on the open-access citation advantage:
     http://opcit.eprints.org/oacitation-biblio.html

     Other studies listed there will also give CHE readers a better idea
     of whether it is indeed "[n]ot yet clear... whether the open-access
     advantage increases citation in the long run or whether the trend
     is similar for other journals."

and the following letter has been published in PLoS:
http://biology.plosjournals.org/perlserv/?request=read-response&doi=10.1371/journal.pbio.0040176

PLOS, PIPE-DREAMS AND PECCADILLOS

Stevan Harnad

I applaud and welcome the results of the Eysenbach (2006) 
<http://dx.doi.org/10.1371/journal.pbio.0040157> study on 1492 
articles published during one 6-month period in one journal 
(PNAS), showing that the Open Access (OA) articles were more 
cited than the non-OA ones. I also agree fully that the findings 
are unlikely to have been an artifact of PLoS's "strong and 
vested interest in publishing results that so obviously endorse 
our existence," nor of the fact that "the author of the article 
is also an editor of an open-access journal" (all quotes are from 
the PloS editorial by MacCallum & Parthasarthy, 2006). 
<http://dx.doi.org/10.1371/journal.pbio.0040176>

However, I am less sure that PloS's and the author's vested 
interests are not behind statements (in both the accompanying 
editorial and the article itself) along the lines that: "solid 
evidence to support or refute" that papers freely available in a 
journal will be more often read and cited than those behind a 
subscription barrier... has been surprisingly hard to find." The 
online bibliography 'The effect of open access and downloads 
('hits') on citation impact' 
<http://opcit.eprints.org/oacitation-biblio.html> records a 
growing number of studies reporting precisely such evidence as of 
2001, including studies based on data from much larger samples of 
journals, disciplines and years than the PloS study on PNAS, and 
they all find exactly the same effect: freely available articles 
are read and cited more.

There can be disagreement about what evidence one counts as 
"solid," but there can be little dispute that prior evidence 
derived from substantially larger and broader-based samples 
showing substantially the same outcome can hardly be described as 
"surprisingly hard to find."

In fact, the only new knowledge from this small, journal-specific 
sample was (1) the welcome finding of how early the OA advantage 
can manifest itself, plus (2) some less clear findings about 
differences between first- and last-author OA practices, plus (3) 
a controversial finding that will most definitely need to be 
replicated on far larger samples in order to be credible: "The 
analysis revealed that self-archived articles are also cited less 
often than OA articles from the same journal."

The latter (3) is a within-journal (one journal, PNAS) finding; 
the overwhelming majority of self-archived articles today (on 
which the prior large-sample OA citation advantage findings are 
based) do not appear in journals with a paid-OA option. Hence on 
the present evidence I have great difficulty in seeing this 
secondary advantage as any more than a paid-OA publisher's 
pipe-dream at this point.

The following, however, is not a pipe-dream, but a peccadillo: 
"no other study has compared OA and non-OA articles from the same 
journal." To be fair, this observation is hedged with "[a]s far 
as we are aware" (but the OA-advantage bibliography is surely 
public knowledge -- or should be among advocates of public access 
to science) and the observation is further qualified with: "and 
[also] controlled for so many potentially confounding factors."

But it has to be stated that of these "potentially confounding" 
variables -- "number of days since publication, number of 
authors, article type, country of the corresponding author, 
funding type, subject area, submission track (PNAS has three 
different ways that authors can submit a paper)... previous 
citation record of the first and last authors... [and] whether 
authors choosing the OA option in PNAS chose to do so for only 
their most important research (they didn't)" -- many are peculiar 
to this particular short-interval, 3-option, single-journal PloS 
study. And several of them (country, subject, year) had already 
been analyzed in papers that had been published before this 2006 
article and were not taken into account despite the fact that 
both their preprints and their postprints had been freely 
accessible since well before publication, and that at least one 
of them (Brody et al. 2005) had been explicitly drawn to the 
author's attention based on a preprint draft well before the 
article was submitted to PloS.

Brody et al. (2005) had found that, alongside the OA citation 
advantage, more downloads in the first six months after 
publication are correlated with more citations 18 months later in 
physics; and Hajjem et al. (2005) had found higher citations for 
OA articles within the same journal/year for 1,307,038 articles 
published across 12 years (1992-2003) in 10 disciplines (Biology, 
Psychology, Sociology, Health, Political Science, Economics, 
Education, Law, Business, Management).

REFERENCES

Brody, T., Harnad, S. and Carr, L. (2005) Earlier Web Usage Statistics
as Predictors of Later Citation Impact. Journal of the American
Association for Information Science and Technology (JASIST) 56.
http://eprints.ecs.soton.ac.uk/10713

Eysenbach, G, (2006) Citation Advantage of Open Access Articles. PLoS
Biology 4(5)
http://dx.doi.org/10.1371/journal.pbio.0040157

Hajjem, C., Harnad, S. and Gingras, Y. (2005) Ten-Year
Cross-Disciplinary Comparison of the Growth of Open Access and How it
Increases Research Citation Impact. IEEE Data Engineering Bulletin 28(4)
pp. 39-47. http://eprints.ecs.soton.ac.uk/11688/

MacCallum, C.J., and Parthasarathy, H. (2006) Open Access Increases
Citation Rate. PLoS Biology 4(5)
http://dx.doi.org/10.1371/journal.pbio.0040176