Facts about SCI and IF

Facts about SCI and IF Facts about SCI and IF

Shaobing PengShaobing Peng

International Rice Research InstituteInternational Rice Research Institute

Presentation at the Northeast Agricultural UniversityPresentation at the Northeast Agricultural University24 August 2006, Harbin24 August 2006, Harbin

OutlineOutline

Web of Science and Science Citation Web of Science and Science Citation Index (SCI)Index (SCI)

Journal Citation Reports (JCR) and Journal Citation Reports (JCR) and Impact Factors (IF)Impact Factors (IF)

Limitations and abuse of IFLimitations and abuse of IF

SCI and IF in relation to ChinaSCI and IF in relation to China

The Thomson CorporationThe Thomson Corporation

Scientific and Healthcare GroupScientific and Healthcare Group

ThomsonThomson ScientificScientific

ThomsonThomson ISIISI

Thomson ISIThomson ISI 3501 Market Street3501 Market StreetPhiladelphia, PA 19104 Philadelphia, PA 19104 USA USA Phone: +1 800 336 4474Phone: +1 800 336 4474Fax: +1 215 386 2911Fax: +1 215 386 2911Web: Web: http://www.isinet.com/http://www.isinet.com/

Room 407, Raycom InfoTech Park Tower A Room 407, Raycom InfoTech Park Tower A No. 2 Kexueyuan South Road No. 2 Kexueyuan South Road Haidian District Haidian District Beijing 100080Beijing 100080P.R. China P.R. China Phone: +86 (10) 8286 2099Phone: +86 (10) 8286 2099Fax: +86 (10) 8286 2088 Fax: +86 (10) 8286 2088 E-mail: E-mail: [email protected]@thomson.com Web: Web: http://www.thomsonscientific.com.cn/http://www.thomsonscientific.com.cn/

History of Thomson ISIHistory of Thomson ISI

Dr. Eugene Garfield, with an academic background Dr. Eugene Garfield, with an academic background in chemistry and library science, in 1958 founded in chemistry and library science, in 1958 founded The Institute for Scientific Information (ISI)The Institute for Scientific Information (ISI)..One of the first publications was One of the first publications was Current Contents/Current Contents/Pharmaco-Medical & Life SciencesPharmaco-Medical & Life Sciences..

The The Science Citation IndexScience Citation Index also developed and also developed and became known as an absolutely unique resource. became known as an absolutely unique resource. Additional citation indexes in the Social Sciences Additional citation indexes in the Social Sciences and Arts & Humanities followedand Arts & Humanities followed..

Technology progressed from print to CD-ROM, and Technology progressed from print to CD-ROM, and eventually the World Wide Web. The result was the eventually the World Wide Web. The result was the Web of Science, Web of Science, which in turn lead to development which in turn lead to development of the of the Web of KnowledgeWeb of Knowledge platform. platform.

ISI Web of KnowledgeISI Web of Knowledge 3.0 Platform 3.0 Platform

Web of Science 7.0Web of Science 7.0

Multidisciplinary Journal CoverageMultidisciplinary Journal Coverage

Science Citation Index Expanded - 6,100+ titlesScience Citation Index Expanded - 6,100+ titles

Social Science Citation Index - 1790 titlesSocial Science Citation Index - 1790 titles

Arts & Humanities Citation Index - 1125 titlesArts & Humanities Citation Index - 1125 titles

A combined 8,600+ journalsA combined 8,600+ journals


Each year, these numbers can be increased or decreasedEach year, these numbers can be increased or decreased

Journal Selection CriteriaJournal Selection Criteria

Each year ISI evaluates approximately 2,000 journals Each year ISI evaluates approximately 2,000 journals for possible coverage in the Web of Science.for possible coverage in the Web of Science.

Basic Journal Publishing Standards (including Basic Journal Publishing Standards (including timeliness of publication, adherence to international timeliness of publication, adherence to international editorial conventions, and english language editorial conventions, and english language bibliographic information)bibliographic information)

ISI also examines the journal's editorial content, ISI also examines the journal's editorial content, the international diversity of it authors and editorsthe international diversity of it authors and editors..

Citation Analysis using ISI data is applied to Citation Analysis using ISI data is applied to determine the journal's citation history and/or the determine the journal's citation history and/or the citation history of its authors and editorscitation history of its authors and editors..

Great Depth of CoverageGreat Depth of Coverage

Science Citation Index Expanded Science Citation Index Expanded To To

19001900

Social Science Citation Index Social Science Citation Index To To

19561956

Arts & Humanities Citation Index Arts & Humanities Citation Index To To

19751975

A total of 34,504,191 documents in the SCI database A total of 34,504,191 documents in the SCI database as of 23 Sept. 2005 as of 23 Sept. 2005


SCI versus SCIESCI versus SCIE

Science Citation Index - 3,700+ titlesScience Citation Index - 3,700+ titles

Science Citation Index Expanded - 6,100+ titlesScience Citation Index Expanded - 6,100+ titles

SCI is print and CD-ROM versions and SCIE is SCI is print and CD-ROM versions and SCIE is

the web versionthe web version

印刷印刷版版光盘光盘版版网络网络版或扩展版版或扩展版

The print version of SCI was firstly published in 1961The print version of SCI was firstly published in 1961

(SCI Annual Author Citation Index, 1997)(SCI Annual Author Citation Index, 1997)

Year

1989 1992 1995 1998 2001 2004 2007

Cu

mu

lati

ve c

itat

ion

0

200

400

600

800

1000

Slope = 141Slope = 141

FirstFirstPaperPaper19891989

FirstFirstCitationCitation

19901990

Journal Citation Reports (JCR) Journal Citation Reports (JCR)

and and

Impact Factors (IF)Impact Factors (IF)

Journal Citation Reports (JCRs) Journal Citation Reports (JCRs)

Every year at end of June, Thomson ISI releases Every year at end of June, Thomson ISI releases Journal Citation Reports for the previous year.Journal Citation Reports for the previous year.

Journals are grouped together according to theirJournals are grouped together according to theirdiscipline. Journals in each group are ranked bydiscipline. Journals in each group are ranked byTotal Cites or Impact Factors.Total Cites or Impact Factors.

The Total Cites value indicates the total numberThe Total Cites value indicates the total numberof times that a journal has been cited by all otherof times that a journal has been cited by all otherjournals included in the ISI database within the journals included in the ISI database within the current JCR yearcurrent JCR year..

The Impact Factors identifies the frequency withThe Impact Factors identifies the frequency withwhich an average article from a journal is cited.which an average article from a journal is cited.

Impact Factors in 2002 Impact Factors in 2002

Total cites in 2002 to articles published in 2000-01Total cites in 2002 to articles published in 2000-01

Number of articles published in 2000-01Number of articles published in 2000-01

Papers published in Nature in 2000 and 2001 were citedPapers published in Nature in 2000 and 2001 were citedon average 30 times in 2002.on average 30 times in 2002.

ISI invented the journal impact factor in ’60sISI invented the journal impact factor in ’60s

Calculations of Indices for Nature Calculations of Indices for Nature

(M. Amin & M. Mabe, Elsevier Science, 2000)

There are 170 categories in JCR Science EditionThere are 170 categories in JCR Science Edition

ISI Began to Publish JCR in 1975 ISI Began to Publish JCR in 1975

Thomson Scientific, Thomson ISI, or ISIThomson Scientific, Thomson ISI, or ISI

ISI Web of Knowledge 3.0 PlatformISI Web of Knowledge 3.0 Platform

Searchable DatabaseSearchable Database Analytical ToolsAnalytical Tools

Web of Web of Science 7.0Science 7.0

CurrentCurrentContentsContents

JournalJournalCitationCitationReportsReports

EssentialEssentialScienceScience

IndicatorsIndicators

SCI-ESCI-E SSCISSCI A&HCIA&HCI ImpactImpactFactorFactor

TotalTotalCitesCites

Limitations and Abuse Limitations and Abuse

of of

Impact Factors (IF)Impact Factors (IF)

Factors Affecting Impact FactorFactors Affecting Impact Factor

The subject area of the journalThe subject area of the journal

The average number of authors per paperThe average number of authors per paper

The type of journal (letters, full papers, reviews)The type of journal (letters, full papers, reviews)

The size of the journalThe size of the journal

The size of the citation measurement windowThe size of the citation measurement window


The average number of references citedThe average number of references cited


RankRank JournalJournal # of papers# of papers1992-20021992-2002

CitesCitesper paperper paper

11 CellCell 4,5354,535 17517522 NatureNature 1,6581,658 12412433 ScienceScience 1,3681,368 10810844 Nature GeneticsNature Genetics 2,0622,062 989855 Genes & DevelopmentGenes & Development 2,9312,931 808066 Journal of Cell BiologyJournal of Cell Biology 5,4805,480 595977 EMBO JournalEMBO Journal 7,1997,199 565688 Molec Cellular BiologyMolec Cellular Biology 8,5308,530 424299 DevelopmentDevelopment 4,7934,793 4141

1010 PNASPNAS 5,2465,246 4141

The Hottest Journals of the DecadeThe Hottest Journals of the DecadeMolecular Biology and GeneticsMolecular Biology and Genetics

(Science Watch, Thomson ISI, 2003)

RankRank JournalJournal # of papers# of papers1992-20021992-2002

CitesCitesper paperper paper

11 ScienceScience 402402 848422 NatureNature 446446 555533 Plant CellPlant Cell 1,8981,898 454544 PNASPNAS 1,3351,335 414155 Plant JournalPlant Journal 2,5492,549 252566 Plant PhysiologyPlant Physiology 6,1786,178 191977 Limno & OceanographyLimno & Oceanography 2,0652,065 181888 Ann Missouri Bot GardeAnn Missouri Bot Garde 367367 171799 Plant Molecular BiologyPlant Molecular Biology 3,2833,283 1717

1010 Journal Animal EcologyJournal Animal Ecology 932932 1616

The Hottest Journals of the DecadeThe Hottest Journals of the DecadePlant & Animal SciencesPlant & Animal Sciences

(Science Watch, Thomson ISI, 2003)

JournalJournal Total Cites (rank)Total Cites (rank) Impact Factors (rank)Impact Factors (rank)

Agronomy (50 journals in this group)

Agron JAgron J

Crop SciCrop Sci

SSSAJSSSAJ

JEQJEQ

5,860 (4)5,860 (4)

8,945 (3)8,945 (3)

13,469 (1)13,469 (1)

7,937 (12)7,937 (12)

1.254 (13)1.254 (13)

0.958 (17)0.958 (17)

1.501 (3)1.501 (3)

1.617 (33)1.617 (33)

Agriculture, Soil Science (27 journals in this group)

Environmental Sciences (134 journals in this group)

ASA-CSSA-SSSA Journal Rankings in 2004ASA-CSSA-SSSA Journal Rankings in 2004

(CSANews, 2005)

The Subject Area of the JournalThe Subject Area of the Journal

Fundamental and pure subject areas have higherFundamental and pure subject areas have higherimpact factors than specialized or applied ones.impact factors than specialized or applied ones.

The top journal in one field may have an impactThe top journal in one field may have an impactfactor lower than the bottom journal in anotherfactor lower than the bottom journal in anotherarea.area.

The average number of authors varies accordingThe average number of authors varies accordingto subject area (lower in social sciences and to subject area (lower in social sciences and higher in fundamental life sciences).higher in fundamental life sciences).

There is the tendency of authors to refer to theirThere is the tendency of authors to refer to theirown work.own work.



Article and Journal Type Article and Journal Type

Journals publish articles in the forms of letter, Journals publish articles in the forms of letter, review, and full papers.review, and full papers.

A short and rapid publication journal publishesA short and rapid publication journal publishesshort articles as letters.short articles as letters.

The “Full paper” journals tend to have lowerThe “Full paper” journals tend to have lowerimpact factors than “Letters” journals. impact factors than “Letters” journals.

Review journals generally have higher impactReview journals generally have higher impactfactors than other types of journals.factors than other types of journals.




Does this mean thatDoes this mean thatsmaller journals aresmaller journals aremore inconsistent inmore inconsistent intheir standard?their standard?

NoNo

An IF of 1.50 for aAn IF of 1.50 for ajournal publishingjournal publishing140 articles is not140 articles is notsignificantly diffe-significantly diffe-rent to another rent to another journal of the samejournal of the samesize with IF of 1.24size with IF of 1.24

Of 30 chemistry journals examined, 24 changed in rank Of 30 chemistry journals examined, 24 changed in rank by up to 11 positions when changing from a two-year by up to 11 positions when changing from a two-year to a five-year impact measurement.to a five-year impact measurement.


Different Types of PapersDifferent Types of Papers

ArticlesArticles

ReviewsReviews

Proceedings papersProceedings papers

EditorialsEditorials

Letters to editorLetters to editor


News itemsNews items

The number of papersThe number of papers

The number of citationsThe number of citations

Inflated Nature’s IF (32.2 in 2004) Inflated Nature’s IF (32.2 in 2004)

The mouse genome paper published in 2002The mouse genome paper published in 2002received 522 citations in 2004.received 522 citations in 2004.

Only 50 out of 1,800 citable items publishedOnly 50 out of 1,800 citable items publishedin 2002-03 received more than 100 citationsin 2002-03 received more than 100 citationsin 2004.in 2004.

The majority of papers received fewer thanThe majority of papers received fewer than20 citations in 2004. 20 citations in 2004.

Therefore, IF is strongly influenced by a smallTherefore, IF is strongly influenced by a smallminority of paper. The 89% of Nature’s IF in minority of paper. The 89% of Nature’s IF in 2004 was generated by just 25% of papers.2004 was generated by just 25% of papers.

(Nature, 435:1003; 2005)(Nature, 435:1003; 2005)

Limitations of Impact Factors Limitations of Impact Factors

It is inappropriate to use IF to rank all types of It is inappropriate to use IF to rank all types of journals in all subject areas.journals in all subject areas.

Journals with IF that differ by less than 25% Journals with IF that differ by less than 25% belong together in the same rank.belong together in the same rank.

The use of the absolute value of an IF to mea-The use of the absolute value of an IF to mea-sure quality should be strongly avoided. sure quality should be strongly avoided.

The use of journal IF for evaluating individualThe use of journal IF for evaluating individualscientists is even more questionable.scientists is even more questionable.


Using the Impact Factors Wisely Using the Impact Factors Wisely

Use IF to compare the same type of journalsUse IF to compare the same type of journalswithin the same discipline.within the same discipline.

Do not depend on IF alone in assessing theDo not depend on IF alone in assessing theusefulness of a journal.usefulness of a journal.

IF should be used with informed peer reviewIF should be used with informed peer reviewin the academic evaluation for tenure.in the academic evaluation for tenure.

Total Cites is more appropriate than IF forTotal Cites is more appropriate than IF forevaluating individual scientists.evaluating individual scientists.

How to Achieve More Citations How to Achieve More Citations

Publish papers in high impact journals.Publish papers in high impact journals.

Publish papers in basic science and applied Publish papers in basic science and applied basic science.basic science.

Publish method papers and review papers.Publish method papers and review papers.

Publish papers in main-stream journals.Publish papers in main-stream journals.

Do not split a major paper into several smallDo not split a major paper into several smallpapers.papers.

SCI and IF in Relation to ChinaSCI and IF in Relation to China

As of September 2004As of September 2004

Out of 6,100+ journals included in SCI, Out of 6,100+ journals included in SCI,

95 journals are from China.95 journals are from China.

Among them, 17 are from Taiwan.Among them, 17 are from Taiwan.

(Institute for Sci. and Tech. Information, China, 2004)(Institute for Sci. and Tech. Information, China, 2004)

China had a 20-foldChina had a 20-fold

increase in its publi-increase in its publi-

cations in the inter-cations in the inter-

national scientific national scientific

journals betweenjournals between

1981 and 2003.1981 and 2003.

China now accounts for over 5% of the world’sChina now accounts for over 5% of the world’sscientific publications.scientific publications.

China remains small in life science, with its shareChina remains small in life science, with its shareof total publications ranging from 0.8% in immu-of total publications ranging from 0.8% in immu-nology to 2% in plant sciencenology to 2% in plant science..

(Nature 431:116, 2004)(Nature 431:116, 2004)

Year World China %

2002 975,072 40,758 4.18

2003 1,111,339 49,788 4.48

Increase % 14.0 22.2

China’ Progress in SCI Papers China’ Progress in SCI Papers


Top six: USA, UK, Japan, Germany, France, and ChinaTop six: USA, UK, Japan, Germany, France, and China

YearYear RankRank UniversityUniversity SCI SCI paperspapers

20032003 11 Tsinghua UniversityTsinghua University 2,2122,21220032003 22 Zhejiang UniversityZhejiang University

20032003 33 Peking UniversityPeking University

20032003 44 Nanjing UniversityNanjing University

20032003 1010 Huazhong Sci & Tech UnivHuazhong Sci & Tech Univ

20032003 1313 Wuhan UniversityWuhan University

20032003 1919 Central South UniversityCentral South University

20032003 3535 China Agricultural UnivChina Agricultural Univ 17417420022002 8181 Huazhong Agric UnivHuazhong Agric Univ 4949

SCI Papers from Chinese UniversitiesSCI Papers from Chinese Universities


RankRank JournalJournal Annual citesAnnual cites1994-20041994-2004

11 J Bio ChemJ Bio Chem 158,000158,000

22 PNASPNAS 121,000121,000

33 NatureNature 108,000108,000

44 ScienceScience 106,000106,000

World averageWorld average 2,0002,000

China averageChina average 300300

(Nanjing Institute of Soil Science, 2005)(Nanjing Institute of Soil Science, 2005)

Average Annual Citation of Journals Average Annual Citation of Journals

From 1995 to 2000,From 1995 to 2000,

67 papers from Scientia Agricultura Sinica67 papers from Scientia Agricultura Sinica

were cited by journals included in SCIwere cited by journals included in SCI

with total cites of 88with total cites of 88..

«« 中国中国农业科学农业科学 »»

((Scientia Agricultura Sinica 34 (6)Scientia Agricultura Sinica 34 (6), 200, 20011))

RankRank JournalJournal Total CitesTotal Cites11 作物作物学报学报 2,0972,09722 中国中国农业科学农业科学 1,6621,66233 土壤土壤学报学报 1,4221,42244 园艺园艺学报学报 1,3871,38755 水土水土保持学报保持学报 1,2451,24566 农业农业工程学报工程学报 94494477 土壤土壤通报通报 71671688 中国中国水稻科学水稻科学 66366399 植物植物病理学报病理学报 606606

1010 植物植物保护学报保护学报 583583

(( 中国中国科技论文与引文数据库科技论文与引文数据库 (CJCR)(CJCR), 200, 2004)4)

20032003 年度总被引频次前年度总被引频次前 1010 名的农学类期刊名的农学类期刊

RankRank JournalJournal IFIF11 水土水土保持学报保持学报 1.7091.70922 作物作物学报学报 1.2021.20233 土壤土壤学报学报 1.1541.15444 中国中国水稻科学水稻科学 0.9750.97555 麦类作物学报麦类作物学报 0.9350.93566 植物营养与肥料学报植物营养与肥料学报 0.8680.86877 中国中国农业科学农业科学 0.7350.73588 园艺园艺学报学报 0.7300.73099 果树学报果树学报 0.7040.704

1010 土壤土壤 0.6860.686

(( 中国中国科技论文与引文数据库科技论文与引文数据库 (CJCR)(CJCR), 200, 2004)4)

20032003 年度影响因子前年度影响因子前 1010 名的农学类期刊名的农学类期刊

谢谢谢谢 !!

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Facts about SCI and IF