Dr. NeesJan van Eck
Centre for Science and Technology Studies (CWTS), Leiden University
Annual Research Directors’ Forum Meeting, CREST, Stellenbosch University
Stellenbosch, November 5, 2014
Multiple perspectives on bibliometricdataBibliometricnetwork analysis and science mapping using VOSviewerand CitNetExplorer

Centre for Science and Technology Studies (CWTS)
•Research center of Leiden University in quantitative studies of science (bibliometricsand scientometrics)
•Bibliometriccontract research
–Monitoring & evaluation
–Advanced analytics
–Training & education
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Short bio
•Master in computer science
•PhD thesis on bibliometricmapping of science
•Since 2009, researcher at Leiden University’s CWTS
–Bibliometricnetwork analysis
–Bibliometricindicators of research performance
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Introduction
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Bibliometricmapping of science
•Bibliometricsis the scientific field that quantitatively studies all kinds of bibliographic data
•Bibliometricmapping of science is about quantitative methods for visually representing scientific literature based on bibliographic data
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Aim of bibliometricmaps
•To provide an overview of the structure of the scientific literature in a certain domain or on a certain topic
•Applications:
–To identify the main research areas within a scientific field
–To get insight into the size of the different areas
–To see how the areas relate to each other
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Types of bibliometricmaps
•Co-authorship maps of
–authors / organizations
•Co-citation maps of
–publications / journals / authors
•Bibliographic coupling maps
–publications / journals / authors / organizations
•Co-occurrence maps of
–keywords / terms extracted from titles and abstracts of articles
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Bibliographic databases
•Contain metadata about publications and their citing publications
•Examples:
–Thomson Reuters’ Web of Science
–Elsevier’s Scopus
–MEDLINE
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–Authors
–Affiliations
–Source
–Volume
–Issue
–Pages
–Publications year
–DOI
–Title
–Abstract
–Keywords
–Document type
–Cited references

Bibliometricnetworks
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Web of Science
Scopus
Citation network
of publications
Co-authorship network
of authors / organizations
Co-citation network
of pubs / authors / journals
Co-occurrence network
of terms
Bibliographic coupling network
of pubs / authors / journals
Bibliographic
database

VOSviewer
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VOSviewer
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VOSviewer
•Web of Science support
•Natural language processing techniques
•State-of-the-art mapping and clustering algorithms
•Powerful visualizations
•Advanced zoom, scroll, and search functionality
•Smart label placement algorithm

Bibliometricmaps in VOSviewer
•Co-authorship maps of
–authors / organizations
•Co-citation maps of
–publications / journals / authors (first author only)
•Bibliographic coupling maps
–publications / journals / authors / organizations
•Co-occurrence maps of
–terms extracted from titles and abstracts of articles
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•2,667 publications in 3 journals (time period 2009– 2013):
–Journal of Informetrics
–Journal of the American Society for Information Science and Technology
–Scientometrics
•Data downloaded from the online version of Web of Science
Demo: Creating different bibliometricmaps using VOSviewer
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Term map
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Bibliographic coupling map of authors
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Co-citation map of journals
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Term map of social science research on global environmental change
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Source: www.worldsocialscience.org/activities/world-social-science-report/the-2013- report/read-changing-global-environments/

Term map of clinical neurology
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Clinical Neurology: Citation density
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(Van Eck et al., PLoSONE, 2012)

Clinical Neurology: Reference density
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Structure of the computational intelligence field 1996-2000
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Structure of the computational intelligence field 1996-2000
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Structure of the computational intelligencefield 2001-2005
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Structure of the computational intelligencefield 2001-2005
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Evolution of the computational intelligence field
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1996-2000
2001-2005

Co-citation map of journals
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Journal application domains
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(Tijssen, JASIST, 2010)

Co-authorship map of universities
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Source: www.leidenranking.com/methodology/additionalresources/

Citation map of Web of Science fields
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Leiden University
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Erasmus University Rotterdam
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Delft University of Technology
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Large-scale mapping and clustering
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CitNetExplorer
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CitNetExplorer
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•Any type of bibliometric network
•Co-citation and bibliographic coupling of publications
•Time dimension is ignored
•At most about 10,000 publications are supported
•Only citation networks of publications
•Direct citations between publications
•Time dimension is explicitly considered
•Millions of publications are supported
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VOSviewer
CitNetExplorer

Why use CitNetExplorer?
•To analyze the structure and development of a research field
–Example: Identifying the main topics in the field of scientometrics and tracing the developments within each topic
•To delineate a research area
–Example: Delineating the literature on science mapping
•To study publication oeuvres
–Example: Identifying the publications of a researcher and analyzing the influence of cited and citing publications
•To support literature reviewing
–Example: Reviewing the literature on the h-index
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•26,002 publications in 14 journals (time period 1945–2013):
•Data downloaded from the online version of Web of Science
Demo: Analyzing the structure and development of scientometrics
American Documentation
ARIST
ASLIB Proceedings
Information Proc.& Manag.
Information Scientist
Information Storage & Retrieval
Journal of Documentation
Journal of Information Science
Journal of Informetrics
JASIS
JASIST
Research Evaluation
Research Policy
Scientometrics
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Structure of scientometric literature
•Citation analysis:
–Foundations
–Research evaluation
–Field normalization
–h-index
–Journal impact factor
•Science mapping
•Co-authorship and collaboration
•Scientometric laws
•Webometrics
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More information
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Websites
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www.vosviewer.com
www.citnetexplorer.nl

Publications on VOSviewer
•Van Eck, N.J., & Waltman, L. (2010). Software survey: VOSviewer, a computer program for bibliometricmapping. Scientometrics, 84(2), 523-538. 10.1007/s11192-009-0146-3
•Van Eck, N.J., & Waltman, L. (2009). How to normalize cooccurrencedata? An analysis of some well-known similarity measures. JASIST, 60(8), 1635-1651. 10.1002/asi.21075
•Waltman, L., Van Eck, N.J., & Noyons, E.C.M. (2010). A unified approach to mapping and clustering of bibliometricnetworks. Journal of Informetrics, 4(4), 629-635. 10.1016/j.joi.2010.07.002
•Van Eck, N.J., Waltman, L., Dekker, R., & Van den Berg, J. (2010). A comparison of two techniques for bibliometricmapping: Multidimensional scaling and VOS. JASIST, 61(12), 2405-2416. 10.1002/asi.21421
•Waltman, L., & Van Eck, N.J. (2013). A smart local moving algorithm for large- scale modularity-based community detection. European Physical Journal B, 86(11), 471. 10.1140/epjb/e2013-40829-0
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Publications on CitNetExplorer
•Van Eck, N.J., & Waltman, L. (2014). CitNetExplorer: A new software tool for analyzing and visualizing citation networks. Journal of Informetrics, 8(4), 802-823. 10.1016/j.joi.2014.07.006
•Van Eck, N.J., & Waltman, L. (2014). Systematic retrieval of scientific literature based on citation relations: Introducing the CitNetExplorertool. In Proceedings of the First Workshop on Bibliometric-enhanced Information Retrieval (BIR 2014), pages 13-20. ceur-ws.org/Vol-1143/paper2.pdf
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Course: BibliometricNetwork Analysis and Science Mapping Using VOSviewer
•April 14-15, 2015
•Leiden University, The Netherlands
•Participants are introduced into the main techniques for bibliometricnetwork analysis and science mapping
•Special attention is paid to applications in a research evaluation and science policy context
•www.cwts.nl
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Thank you for your attention!
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