Re: Citation indexing and Re: Ejournal use data, was: Elsevier andcancellations

[David Goodman <dgoodman@phoenix.Princeton.EDU>]

Citation indexing is one of the key tools, and can give potentially two
types of data:

First, for or the journal as a whole, it can tell how much it is cited
(either total citations to all article in the journal, or citations per
article published, known as the impact factor), and by what journals it is
cited. This information is not exactly free, but is available as the CD or
Web product Journal Citation Reports. This however is information about
the content of the journal, not the content of the journal as it applies
to any one University's interests. There are , for example, many
theoretical ecology titles that are not that much used by the world in
general, but are certainly key journals to my library; there are many
hematology journals very highly cited by those in that subject, but only
slightly used or cited here.)

Second, Information about citations as it applies to any one institution
can be obtained from Science citation Index. Unfortunately it can not be
done with Web of Science, but only the versions on Dialog (& other such
services). Basically, you search for a title as citation source, and your
institution as citing location. This is quite inexpensive if one doesn't
need to analyze further. To see what articles are being cited or the
departments of those citing them is, because of the Dialog pricing
structure, very expensive (unless one does this, there's a ambiguity about
citing institution, as this is not a standardized field. ISI also can
supply all this for an institution as a customized service, for a fee. I
have in fact done this for all Biology and Neuroscience journals that
Princeton subscribes to, and the Rutgers chemistry Librarian, Howard Dess,
published an article about this in "Science and Technology Libraries."
(Note that this is not the same as just seeing where a University's
faculty publish their papers, which is typically a much more restricted
group of titles.)

But this citation use is only part of the use: It only measures use that
results in references in formally published papers. It doesn't reflect
what is read as background but not cited. It doesn't reflect unpublished
theses. It doesn't reflect publication as technical reports, or as books.  
It doesn't reflect student papers. It doesn't reflect class assignments.
It doesn't reflect what was found not useful, but which had to be examined
to make that determination. However, it is generally found to roughly
correlate with usage as measured by reshelving studies, except that at
least in biology review journals are typically even higher in the
reshelving use than the citation use (data for my library are in
preparation). One can certainly argue that in a scholarly institution
citation data offers the best single measurement. And in the absence of
data for a particular institution, the JCR data can be very useful indeed.
In both cases, they can of course be validly used only with awareness of
their limitations.

David Goodman, Princeton University
Biology Library				 dgoodman@princeton.edu   609-258-3235

_____

On Fri, 20 Aug 1999 Hunger99@aol.com wrote:

> Didn't Garfield pioneer this area by looking at citation indexing?  
> Doesn't Science Citation Indexing still put out numbers on what journals
> and what articles have the most impact in a field?  Are these not better,
> more direct, measures than how often a journal is accessed?  It would
> appear that accessing may be related to the impact of a journal or
> article, but what we would like to know for understanding progress and
> development in a field is impact, or some such measure. Aren't citation
> measures available to librarians for free from SCI?  And SSCi? dh
> 
>