Overlay Maps of Science Ismael Rafols 1 2

Overlay Maps of Science Ismael Rafols 1, 2, Alan Porter 2 and Loet Leydesdorff 3 1 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 2009 18 factors 222 subject categories Infectious Diseases Ecol Sci Geosciences Agri Sci Env Sci & Tech Clinical Med Chemistry Matls Sci Engineering Biomed Sci Cognitive Sci. Psychology Health & Social Issues Business & MGT Physics Computer Sci. Econ. Polit. & Geography Social Studies Rafols, Porter and Leydesdorff (2010)

Ecol Sci Infectious Diseases Geosciences Agri Sci Env Sci & Tech Clinical Med Chemistry Matls Sci Engineering Biomed Sci Cognitive Sci. Psychology Health & Social Issues Business & MGT Physics Computer Sci. Econ. Polit. & Geography Social Studies Rafols, Porter and Leydesdorff (2010)

Global Map of Science 2009 4 disciplinary areas 222 subject categories Environmental S&T Biomedical Sciences Physical Sciences Social Sciences Rafols, Porter and Leydesdorff (2010)

Environmental S&T Biomedical Sciences Physical Sciences Social Sciences Rafols, Porter and Leydesdorff (2010)

References Global Maps of Science • 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, 60(9), 1823 -1835. Overlay • Rafols, I. , Porter, A. L. and Leydesdorff, L. (2010) Overlay science maps: a new tool for research policy and library management. Journal of the American Society for Information Science and Technology 61(9), 871– 1887. • Rafols, I. and Meyer, M. (2010) Diversity and Network Coherence as indicators of interdisciplinarity: case studies in bionanoscience. Scientometrics, 82(2), 263 -287.