How to compare research impact of toll- vs. open -access research

Garfield, Eugene garfield at CODEX.CIS.UPENN.EDU
Wed Apr 14 21:46:29 EDT 2004

The results obtained for computer science by analysis of CiteSeer are
distorted for a variety of reasons. They cannot be compared with the
literature of e.g. life sciences. Computer science is heavily dependent upon
conference literature. I cannot comment upon the physics literature, but
there are other studies which seem to indicate that readership increases
will not necessarily be followed by increased citation impact.

In one study of a single chemical journal that I refereed there were about
100 readerships for each citation of that journal, but there did not seem to
be any perceptible increase of citation by the research literature.
Undoubtedly the web will increase apparent readership of literature, but
that will not necessarily change the population of relevant researchers who
are in a position to cite particular studies.

I do not think the ISI study is definitive but it is not irrelevant. Gene

Eugene Garfield, PhD. email garfield at
tel 215-243-2205   fax 215-387-1266
President, The Scientist
Chairman Emeritus, ISI
home page:
Past President, American Society for Information Science and Technology

-----Original Message-----
From: Stevan Harnad [mailto:harnad at ECS.SOTON.AC.UK]
Sent: Wednesday, April 14, 2004 8:13 PM
Subject: Re: [SIGMETRICS] How to compare research impact of toll- vs.
open-access research

Prior Topic Thread:

    "How to compare research impact of toll- vs. open-access research"

---------- Forwarded message ----------
Date: Wed, 14 Apr 2004 23:11:59 +0100
From: "Garfield, Eugene" <garfield at>

Fyi and posting. Gene

Eugene Garfield, PhD.
President, The Scientist LLC.
Chairman Emeritus, ISI

Attached is the news release regarding Open Access journals covered by Web
of Science.


Rodney Yancey, Manager, Corporate Communications, Thomson Scientific

    [Amsci Forum Moderator's Note: The ISI press release says:

        "Today, Thomson ISI... announced that journals published in the
        new Open Access (OA) model are beginning to register impact in
        the world of scholarly research...  Of the 8,700 selected journals
        currently covered in Web of Science, 191 are OA journals... [A
        study on] whether OA journals perform differently from other
        journals in their respective fields [found] that there was no
        discernible difference in terms of citation impact or frequency
        with which the journal is cited."

    But if you want to get a better idea of the effect of OA on impact,
    don't just compare the 2% of ISI journals that are OA journals
    with the 98% that are not, to find that they are equal in impact
    (for this may well be comparing apples with oranges). Compare the
    much higher percentage of *articles* from the 98% non-OA journals
    that have been made OA by their authors -- by self-archiving
    them -- with articles (from the very same journals and volumes)
    that have *not* been made OA by their authors: You will find that
    there is indeed a discernible difference in terms of frequency
    with which the *article* is cited, and that that difference
    is from 250%-550% in favor of the articles that their authors
    have made OA! That is what an ongoing series of comparisons
    based on a 10-year sample of the same ISI database across all
    disciplines is revealing (in computer science and physics so far):
    Stevan Harnad.]


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