An algorithm for drawing general undirected graphs
Information Processing Letters
Introduction to Modern Information Retrieval
Introduction to Modern Information Retrieval
Dynamic and evolutionary updates of classificatory schemes in scientific journal structures
Journal of the American Society for Information Science and Technology
Algorithmic procedure for finding semantically related journals
Journal of the American Society for Information Science and Technology
Journal of the American Society for Information Science and Technology
Interdisciplinarity in science: a tentative typology of disciplines and research areas
Journal of the American Society for Information Science and Technology
Journal of the American Society for Information Science and Technology
Classification and powerlaws: The logarithmic transformation: Research Articles
Journal of the American Society for Information Science and Technology
Visualization of the citation impact environments of scientific journals: An online mapping exercise
Journal of the American Society for Information Science and Technology
Visualizing the marrow of science
Journal of the American Society for Information Science and Technology
Journal of the American Society for Information Science and Technology
A global map of science based on the ISI subject categories
Journal of the American Society for Information Science and Technology
Toward a consensus map of science
Journal of the American Society for Information Science and Technology
Journal of the American Society for Information Science and Technology
Journal of the American Society for Information Science and Technology
Journal of the American Society for Information Science and Technology
A rejoinder on energy versus impact indicators
Scientometrics
Scientometrics
Mapping (USPTO) patent data using overlays to Google Maps
Journal of the American Society for Information Science and Technology
A new methodology for constructing a publication-level classification system of science
Journal of the American Society for Information Science and Technology
Journal of the American Society for Information Science and Technology
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The aggregated journal-journal citation matrix—based on the Journal Citation Reports (JCR) of the Science Citation Index—can be decomposed by indexers or algorithmically. In this study, we test the results of two recently available algorithms for the decomposition of large matrices against two content-based classifications of journals: the ISI Subject Categories and the field-subfield classification of Glänzel and Schubert (2003). The content-based schemes allow for the attribution of more than a single category to a journal, whereas the algorithms maximize the ratio of within-category citations over between-category citations in the aggregated category-category citation matrix. By adding categories, indexers generate between-category citations, which may enrich the database, for example, in the case of inter-disciplinary developments. Algorithmic decompositions, on the other hand, are more heavily skewed towards a relatively small number of categories, while this is deliberately counter-acted upon in the case of content-based classifications. Because of the indexer effects, science policy studies and the sociology of science should be careful when using content-based classifications, which are made for bibliographic disclosure, and not for the purpose of analyzing latent structures in scientific communications. Despite the large differences among them, the four classification schemes enable us to generate surprisingly similar maps of science at the global level. Erroneous classifications are cancelled as noise at the aggregate level, but may disturb the evaluation locally. © 2009 Wiley Periodicals, Inc.