How are "fields" defined in bibliometrics.

[Loet Leydesdorff]

> How are fields defined? I am interested in sub-areas of Computer Science
but I cannot find any definition of which are said sub-areas, and I
realized that probably the same problem was solved a a higher lavel,
when the different fields fo science were defined.

Dear Jacques, 

There have been different attempts to delineate fields in terms of journals,
co-citation structures, etc. Sometimes, categories have been designed ex
ante in tree-like structure. 

A sophisticated and literarily warranted classification is that of the
Library of Congress. In bibliometrics, one often uses the ISI Subject
Categories, but these are fixed since a long time and fuzzy in the
overlappings. Algorithmic classifications are also available.

See, for example, as an introduction: 
Ismael Rafols & Loet Leydesdorff (2009). Content-based and Algorithmic
Classifications of Journals: Perspectives on the Dynamics of Scientific
Communication and Indexer Effects, Journal of the American Society for
Information Science and Technology 60(9) 1823-1835. 

With 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 
loet at leydesdorff.net ; http://www.leydesdorff.net/