How to compare research impact of toll- vs. open-access research
harnad at ecs.soton.ac.uk
Fri Nov 14 17:29:15 EST 2003
[Posted with permission from Michael Kurtz, Astrophysics, Harvard]
On Fri, 14 Nov 2003, Michael Kurtz wrote:
> You may be interested in:
> which is a report by the librarian liason of the AAS Pub board meeting.
> The relevant paragraph (at the end) is:
> Finally, there was a very interesting brief report from Greg Schwarz
> (from the ApJ editorial office) on some work he's doing tracking
> citation rates of papers published in the ApJ based on whether they were
> posted on astro-ph or not. He studied samples from July-Dec. 1999 and
> July-Dec. 2002. The first interesting point is that 72% of the papers
> published in the latter period had appeared on astro-ph, although the
> submission rate to the server seems to be leveling off. He also noted
> that the number of authors per paper has been increasing along with the
> total length and that most astro-ph submissions are after acceptance by
> the journal. The really fascinating conclusion he's drawn, at least from
> my perspective, is that ApJ papers that were also on astro-ph have a
> citation rate that is _twice_ that of papers not on the preprint server.
> Moreover, this higher citation rate appears to continue once the time
> gap disappears (that is, papers on astro-ph are viewed about nine months
> ahead of the journal paper, but after several years of availability, the
> astro-ph papers are still being cited at a significantly higher rate).
> You have shown some similar work already, but this seems nicely done.
> With the majority of ApJ papers going to astro-ph those which are not
> preprinted (and which are less referenced) seem the oddballs.
> I have been assuming that the higher citation rates for papers which are
> preprinted was due to the preprinting; perhaps the effect is that lower
> quality/interest papers are not preprinted.
Can I ask for a clarification (because the word "preprinted," unlike
"self-archived," is somewhat ambiguous): Are you specifically referring
here to the prepublication part of an article's timeline, your point being
that in astrophysics, where the publishers' versions are all effectively
"open access" by the time they appear (in that they are all available to
the entire worldwide astrophysical research community via site-licenses
to the relatively small and closed group of journals involved), there are
*still* twice as many citations of those papers that were self-archived
before publication (as either pre-refereeing preprints or post-refereeing
postprints or both) than to those that only became openly accessible
when they became available as from the publisher?
That would be very useful news both for the value of open access to
eprints (preprints and postprints) in general and the value of prepublication
self-archiving in particular, suggesting that (if we take Steve Lawrence's
figures for the overall citation advantage of free online access to eprints
over the its alternatives -- online or on-paper -- which is a citation
advantage of 4.5) we see that a two-fold advantage already comes from
free access to the prepublication phase alone.
The causality, of course, is uncertain here, as you note: Is it that
earlier open-access enhances the citation counts, or that the better
articles are the ones that are being self-archived earlier?
In any case, it is certainly a vote both for open access and for early
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