A Global Map of Science Based on the ISI Subject Categories -- preprint version available

Sun Oct 28 03:46:00 EDT 2007

Dear David, 

"Once we consider the weights of the links among fields, however, it becomes
clear that the structure of science is more like the letter U than like a
ring, with the social sciences at one terminal and engineering at other,
joined mainly by a backbone of medicine, molecular biology, chemistry, and
physics. Because our map shows the pattern of citations to research articles
published within five years, it represents what de Sola Price called the
“research frontier,” (23) rather than the long-term interdependencies among
fields. For example, while mathematics are essential to all natural
sciences, the field of mathematics is not central in our map because only
certain subfields (e.g. areas of physics and statistics) rely heavily on the
most recent developments in pure mathematics and contribute in return to the
research agenda in that field."

from: Rosvall, M., & Bergstrom, C. T. (2007). Maps of Information Flow
Reveal Community Structure In Complex Networks. eprint arXiv: 0707.0609, at
p. 5.

"Finally, dark gray shows the
<http://www3.interscience.wiley.com/giflibrary/12/ldquo.gif> cold
<http://www3.interscience.wiley.com/giflibrary/12/rdquo.gif> ones that were
not identified by factor analysis and therefore belong to no subject area.
Our findings coincide with those of Boyack et al. ([
<http://www3.interscience.wiley.com/cgi-bin/fulltext/116312048/main.html,ftx
_abs#BIB1> 2005]), in that certain categories are not adequately represented
by the documents that make them up (e.g., in Mathematics)."

from: Félix de Moya-Anegón, B. V.-Q., Zaida Chinchilla-Rodríguez, Elena
Corera-Álvarez, Francisco J. Munoz-Fernández, Victor Herrero-Solana (2007).
Visualizing the marrow of science Journal of the American Society for
Information Science and Technology, (forthcoming; DOI: 10.1002/asi.20683).

Thus, we seem to agree :-)

Best wishes, 

Loet

  _____  

Loet Leydesdorff 
Amsterdam School of Communications Research (ASCoR), 
Kloveniersburgwal 48, 1012 CX Amsterdam. 
Tel.: +31-20- 525 6598; fax: +31-20- 525 3681 
 <mailto:loet at leydesdorff.net> loet at leydesdorff.net ;
<http://www.leydesdorff.net/> http://www.leydesdorff.net/ 

  _____  

From: ASIS&T Special Interest Group on Metrics
[mailto:SIGMETRICS at LISTSERV.UTK.EDU] On Behalf Of David E. Wojick
Sent: Monday, October 22, 2007 4:30 PM
To: SIGMETRICS at LISTSERV.UTK.EDU
Subject: Re: [SIGMETRICS] A Global Map of Science Based on the ISI Subject
Categories -- preprint version available

Dear Loet, this is indeed interesting. Why did mathematics did not make the
14 factor cut, or is this explained in the paper? Is it that no one else
cites math?

Your 172 category network is clearly 3 dimensional. (My rule of thumb is
that if you cannot draw it without a lot of lines crossing then the topology
is 3D.) It might be useful to view it in 3D with rotation and zoom, to
better see the sub-structures. Have you considered this?

Best wishes,

David Wojick

A Global Map  <http://www.leydesdorff.net/map06/texts/index.htm> of Science
Based on the ISI Subject Categories

Loet Leydesdorff & Ismael Rafols

 <http://www.leydesdorff.net/map06/texts/map06.pdf> <click here for pdf>

 <http://www.leydesdorff.net/map06/index.htm> <click here for the maps>

The ISI subject categories classify journals included in the Science
Citation Index (SCI). The aggregated journal-journal citation matrix
contained in the Journal Citation Reports can be aggregated on the basis of
these categories. This leads to an asymmetrical transaction matrix (citing
versus cited) which is much more densely populated than the underlying
matrix at the journal level. Exploratory factor analysis leads us to opt for
a fourteen-factor solution. This solution can easily be interpreted as the
disciplinary structure of science. The nested maps of science (corresponding
to 14 factors, 172 categories, and 6,164 journals) are brought online at
http://www.leydesdorff.net/map06/index.htm. An analysis of interdisciplinary
relations is pursued at three levels of aggregation using the newly added
ISI subject category of "Nanoscience & nanotechnology." The journal level
provides the finer grained perspective. Errors in the attribution of
journals to the ISI subject categories are averaged out so that the factor
analysis can reveal the main structures. The mapping of science can,
therefore, be comprehensive at the level of ISI subject categories.

  _____  

Loet Leydesdorff
Amsterdam School of Communications Research (ASCoR)
Kloveniersburgwal 48, 1012 CX Amsterdam
Tel.: +31-20- 525 6598; fax: +31-20- 525 3681
loet at leydesdorff.net ; http://www.leydesdorff.net/

Now available: The
<http://www.universal-publishers.com/book.php?method=ISBN&book=1581129378>
Knowledge-Based Economy: Modeled, Measured, Simulated. 385 pp.; US$ 18.95 
The
<http://www.universal-publishers.com/book.php?method=ISBN&book=1581126956>
Self-Organization of the Knowledge-Based Society; The
<http://www.universal-publishers.com/book.php?method=ISBN&book=1581126816>
Challenge of Scientometrics

-- 

"David E. Wojick, PhD" <WojickD at osti.gov>
Senior Consultant for Innovation
Office of Scientific and Technical Information
US Department of Energy
http://www.osti.gov/innovation/
391 Flickertail Lane, Star Tannery, VA 22654 USA
540-858-3136

http://www.bydesign.com/powervision/resume.html provides my bio and client
list. 
http://www.bydesign.com/powervision/Mathematics_Philosophy_Science/ presents
some of my own research on information structure and dynamics. 

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