Facts about SCI and IF Shaobing Peng International Rice Research Institute Presentation at the Northeast Agricultural University 24 August 2006, Harbin
Outline Web of Science and Science Citation Index (SCI) Journal Citation Reports (JCR) and Impact Factors (IF) Limitations and abuse of IF SCI and IF in relation to China
The Thomson Corporation Scientific and Healthcare Group ThomsonScientific ThomsonISI
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History of Thomson ISI Dr. Eugene Garfield, with an academic background in chemistry and library science, in 1958 founded The Institute for Scientific Information (ISI). One of the first publications was Current Contents/ Pharmaco-Medical & Life Sciences. The Science Citation Index also developed and became known as an absolutely unique resource. Additional citation indexes in the Social Sciences and Arts & Humanities followed. • Technology progressed from print to CD-ROM, and • eventually the World Wide Web. The result was the • Web of Science, which in turn lead to development • of the Web of Knowledge platform.
Web of Science 7.0 • Science Citation Index Expanded - 6,100+ titles • Social Science Citation Index - 1790 titles • Arts & Humanities Citation Index - 1125 titles Multidisciplinary Journal Coverage A combined 8,600+ journals Each year, these numbers can be increased or decreased
Journal Selection Criteria Basic Journal Publishing Standards (including timeliness of publication, adherence to international editorial conventions, and english language bibliographic information) ISI also examines the journal's editorial content, the international diversity of it authors and editors. Citation Analysis using ISI data is applied to determine the journal's citation history and/or the citation history of its authors and editors. Each year ISI evaluates approximately 2,000 journals for possible coverage in the Web of Science.
Web of Science 7.0 • Science Citation Index Expanded To 1900 • Social Science Citation Index To 1956 • Arts & Humanities Citation Index To 1975 Great Depth of Coverage A total of 34,504,191 documents in the SCI database as of 23 Sept. 2005
Science Citation Index - 3,700+ titles • Science Citation Index Expanded - 6,100+ titles • SCI is print and CD-ROM versions and SCIE is • the web version SCI versus SCIE 光盘版 印刷版 网络版 或 扩展版
First Paper 1989 First Citation 1990 Slope = 141
Journal Citation Reports (JCR) and Impact Factors (IF)
Journal Citation Reports (JCRs) Every year at end of June, Thomson ISI releases Journal Citation Reports for the previous year. Journals are grouped together according to their discipline. Journals in each group are ranked by Total Cites or Impact Factors. The Total Cites value indicates the total number of times that a journal has been cited by all other journals included in the ISI database within the current JCR year. The Impact Factors identifies the frequency with which an average article from a journal is cited.
Impact Factors in 2002 Total cites in 2002 to articles published in 2000-01 Number of articles published in 2000-01 Papers published in Nature in 2000 and 2001 were cited on average 30 times in 2002. ISI invented the journal impact factor in ’60s
ISI Began to Publish JCR in 1975 There are 170 categories in JCR Science Edition
Thomson Scientific, Thomson ISI, or ISI ISI Web of Knowledge 3.0 Platform Searchable Database Analytical Tools Web of Science 7.0 Current Contents Journal Citation Reports Essential Science Indicators SCI-E SSCI A&HCI Impact Factor Total Cites
Limitations and Abuse of Impact Factors (IF)
Factors Affecting Impact Factor The subject area of the journal The average number of authors per paper The type of journal (letters, full papers, reviews) The size of the journal The size of the citation measurement window The average number of references cited (M. Amin & M. Mabe, Elsevier Science, 2000)
The Hottest Journals of the Decade Molecular Biology and Genetics (Science Watch, Thomson ISI, 2003)
The Hottest Journals of the Decade Plant & Animal Sciences (Science Watch, Thomson ISI, 2003)
ASA-CSSA-SSSA Journal Rankings in 2004 Journal Total Cites (rank) Impact Factors (rank) Agronomy (50 journals in this group) 5,860 (4) 8,945 (3) 13,469 (1) 7,937 (12) 1.254 (13) 0.958 (17) 1.501 (3) 1.617 (33) Agron J Crop Sci SSSAJ JEQ Agriculture, Soil Science (27 journals in this group) Environmental Sciences (134 journals in this group) (CSANews, 2005)
The Subject Area of the Journal Fundamental and pure subject areas have higher impact factors than specialized or applied ones. The top journal in one field may have an impact factor lower than the bottom journal in another area. The average number of authors varies according to subject area (lower in social sciences and higher in fundamental life sciences). There is the tendency of authors to refer to their own work. (M. Amin & M. Mabe, Elsevier Science, 2000)