http://users.fmg.uva.nl/lleydesdorff/map06/texts/index.htm
A Global Map of Science Based on the ISI Subject Categories
map http://users.fmg.uva.nl/lleydesdorff/map06/index.htm
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.
| Source | Loet Leydesdorff & Ismael Rafols |
| Difficulty | N/A |
| Compatibility | N/A |
| Rating | 0 |
| Language | en |