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

[David E. Wojick]

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



<http://www.leydesdorff.net/map06/texts/index.htm>A Global Map 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>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
<mailto:loet at leydesdorff.net>loet at leydesdorff.net ; 
<http://www.leydesdorff.net/>http://www.leydesdorff.net/


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