Green OA Impact Advantage: Within- vs Between-Journal Comparisons

[Stevan Harnad <amsciforum@gmail.com>]

Miguel, Sandra, Zaida Chinchilla-Rodriguez & Felix de Moya-Anegon 
(2011) Open Access and Scopus: A New Approach to Scientific 
Visibility From the Standpoint of Access. Journal of the American 
Society for Information Science and Technology (JASIST) 
http://dx.doi.org/10.1002/asi.21532

ABSTRACT: The last few years have seen the emergence of several 
open access (OA) options in scholarly communication, which can be 
grouped broadly into two areas referred to as gold and green 
roads. Several recent studies have shown how large the extent of 
OA is, but there have been few studies showing the impact of OA 
in the visibility of journals covering all scientific fields and 
geographical regions.This research presents a series of 
informative analyses providing a broad overview of the degree of 
proliferation of OA journals in a data sample of about 17,000 
active journals indexed in Scopus. This study shows a new 
approach to scientific visibility from a systematic combination 
of four databases: Scopus, the Directory of Open Access Journals, 
Rights Metadata for Open Archiving (RoMEO)/Securing a Hybrid 
Environment for Research Preservation and Access (SHERPA), and 
SciMago Journal Rank] and provides an overall, global view of 
journals according to their formal OA status. The results 
primarily relate to the number of journals, not to the number of 
documents published in these journals, and show that in all the 
disciplinary groups, the presence of green road journals widely 
surpasses the percentage of gold road publications. The 
peripheral and emerging regions have greater proportions of gold 
road journals. These journals belong for the most part to the 
last quartile. The benefits of OA on visibility of the journals 
are to be found on the green route, but paradoxically, this 
advantage is not lent by the OA, per se, but rather by the 
quality of the articles/journals themselves regardless of their 
mode of access.

Hyperlinked version of this commentary:
http://openaccess.eprints.org/index.php?/archives/811-guid.html

Miguel et al's (2011) article is very timely and useful in its 
SCOPUS-based quantification of the proportion of journals that 
are Green, Gold and Gray journals, across fields and countries.

It is also very useful in reviewing and supporting the advantages 
and primacy of Green OA.

But one of Miguel et al's conclusions is incorrect:
"The benefits of OA on visibility of the journals are to be found 
on the green route, but paradoxically, this advantage is not lent 
by the OA, per se, but rather by the quality of the 
articles/journals themselves regardless of their mode of access."
The authors show, correctly, that, on average, Green journals 
(i.e., journals that formally endorse their authors' right to 
self-archive their articles) have higher impact factors than Gold 
and non-Green journals, across all fields.

These data are welcome, but they merely confirm what has been 
known for years now: Most of the top journals are already Green. 
(Over 60% of journals have been Green for many years now, as 
SHERPA Romeo has been showing -- and those include most of the 
top journals in just about every field. The top journals often 
also tend to have higher impact factors.)

But (alas!) it does not follow from the fact that Green journals 
have higher impact factors that their authors are actually 
providing Green OA! Far from it.

Between 5 and 25% of articles are being made Green OA (depending 
on field) today, and it is only Green OA mandates that 
significantly increase those percentages.

(Apart from the effect of mandates, the Green OA percentages 
themselves have been increasing glacially slowly across the 
years. And Green OA mandates apply to all articles, not just to 
articles in Green OA journals.)

The reason it became evident to universities and funders that 
Green OA mandates were necessary was precisely because Green 
publishers endorsements of their authors' right to provide Green 
OA was not enough to induce most authors to provide Green OA.

Miguel et al's article is helpful in that it supports Green OA 
(hence, indirectly, it also supports Green OA mandates), but it 
has unfortunately misinterpreted both the causality and the 
methodology underlying the studies demonstrating the Green OA 
citation advantage:

Miguel et al interpret the higher average impact factor of Green 
journals as the cause underlying the widely reported OA citation 
impact advantage, suggesting that it is not OA that causes the 
higher impact, but just the fact that more high-impact journals 
endorse Green OA.

But most of the studies demonstrating the OA impact advantage are 
based on comparing on comparing articles within the very same 
journal (Green OA articles vs. non-OA articles; Gold OA journals 
are of course omitted in these within-journal comparisons, 
because all of their articles are OA, so one cannot do compare 
the impact of OA and non-OA articles).

Hence all the reports of the Green OA impact advantage are based 
on within-journal effects, not between-journal effects.

Hence it is not relevant for the many reports of the Green OA 
advantage whether the journals are Green or Gray (Gold journals 
being eliminated in any case, for methodological reasons). It is 
also irrelevant what proportions of all journals are Green, Gold 
or Gray.

I think Miguel et al misinterpretation arises from two sources 
(not unique to Miguel et al):

(1) A general tendency to conceive of OA as a journal effect 
rather than an article effect (because of a narrow focus on 
journals, especially Gold OA journals, as the model for OA).

(2) A systematic ambiguity about the meaning of "Green," 
depending on whether one is thinking at the journal level or the 
article level: (2a) At the journal level, "Green" (unlike "Gold") 
just means that the journal endorses author-provided Green OA -- 
it does not mean that the journal (or its authors) actually 
provides Green OA!

(2b) At the article level, "Green" means that the article has 
actually been made Green OA. Apart from that one point, the 
Miguel et al article contains informative and useful 
between-journal data on Green and Gold OA, across fields and 
geographic areas.

It is only one of Miguel et al's conclusions ' that their 
between-journal data showing that Green OA journals have higher 
impact factors than both Gold OA and Gray journals somehow 
explain or invalidate the many within-journal studies 
demonstrating that Green OA articles within the same journal have 
higher citation counts than non-OA articles -- that does not 
follow from the evidence (and cannot follow, methodologically or 
logically).

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