Overlay Maps of Science Ismael Rafols 1 2

Overlay Maps of Science Ismael Rafols 1, 2, Alan Porter 2 and Loet Leydesdorff 3 2 SPRU, University of Sussex, Brighton 2 School of Public Policy, Georgia Institute Technology, Atlanta 3 Amsterdam School of Comm. Res. (ASCo. R), Univ. Amsterdam

Global Map of Science, 2006 175 SCI Subject Categories Ecology Agriculture Geosciences Infectious Diseases Biomed Sci Environ Sci Clinical Med Chemistry Matls Sci Engineering Neurosciences Computer Sci. Physics General Med Leydesdorff and Rafols (2009)

Global Map of Science, 2006 175 SCI Subject Categories Ecology Agriculture Geosciences Infectious Diseases Biomed Sci Environ Sci Clinical Med Chemistry Matls Sci Engineering Neurosciences General Med Computer Sci. Physics

Global Map of Science, 2007 221 SCI-SSCI Subject Categories Agri Sci Env Sci & Tech Ecol Sci Infectious Diseases Geosciences Clinical Med Chemistry Matls Sci Engineering Biomed Sci Cognitive Sci. Health & Social Issues Psychology Physics Business & MGT Computer Sci. Social Studies Econ. Polit. & Geography Rafols, Porter and Leydesdorff (2009)

Global Map of Science, SCI-SSCI 2007 Env Sci & Tech Agri Sci Ecol Sci Infectious Diseases Clinical Med Geosciences Chemistry Matls Sci Engineering Biomed Sci Cognitive Sci. Health & Social Issues Psychology Physics Business & MGT Computer Sci. Social Studies Econ. Polit. & Geography

References Maps • Leydesdorff, L. and Rafols, I. (2009) A Global Map of Science Based on the ISI Subject Categories. Journal of the American Society for Information Science and Technology, 60(2), 348 -362. • Rafols, I. and Leydesdorff, L. (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. DOI: 10. 1002/asi. 21086. Overlay • Rafols, I. , Porter, A. L. and Leydesdorff, L. (in preparation) Overlay science maps: a new tool for research evaluation. • Rafols, I. and Meyer, M. (2009) Diversity and Network Coherence as indicators of interdisciplinarity: case studies in bionanoscience. Scientometrics, DOI 10. 1007/s 11192 -009 -0041 -y.