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An Experimental Comparison of Bibliometric Mapping Techniques. Nees Jan van Eck , Ludo Waltman, Rommert Dekker Erasmus University Rotterdam, The Netherlands {nvaneck,lwaltman,rdekker}@few.eur.nl Jan van den Berg Delft University of Technology, The Netherlands [email protected] - PowerPoint PPT Presentation
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An Experimental Comparison of Bibliometric Mapping Techniques
Nees Jan van Eck, Ludo Waltman, Rommert Dekker
Erasmus University Rotterdam, The Netherlands{nvaneck,lwaltman,rdekker}@few.eur.nl
Jan van den BergDelft University of Technology, The Netherlands
10th International Conference on Science and Technology Indicators
Vienna, September 18, 2008 1
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Bibliometric mapping
Similarity measureDirect Indirect
Jaccard Cosine Association strength … Pearson
correlation Cosine …
Unit of analysisAuthors Journals Words/terms Web pages …
Mapping techniqueDistance based Graph based
MDS VxOrd VOS … Pajek Pathfinder networks …
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Bibliometric mapping
Similarity measureDirect Indirect
Jaccard Cosine Association strength … Pearson
correlation Cosine …
Unit of analysisAuthors Journals Words/terms Web pages …
Mapping techniqueDistance based Graph based
MDS VxOrd VOS … Pajek Pathfinder networks …
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Data sets
Similarity measureDirect Indirect
Jaccard Cosine Association strength … Pearson
correlation Cosine …
Mapping techniqueDistance based Graph based
MDS VxOrd VOS … Pajek Pathfinder networks …
1. Journals in economics, management, and operations research 2001-2005 ISI categories: business; business, finance; economics;
management; and operations research & management science 376 journals
2. Terms in computational intelligence 2001-2005 337 terms
Unit of analysisAuthors Journals Words/terms Web pages …
Unit of analysisAuthors Journals Words/terms Web pages …
5
Similarity measures
Similarity measureDirect Indirect
Jaccard Cosine Association strength … Pearson
correlation Cosine …
Mapping techniqueDistance based Graph based
MDS VxOrd VOS … Pajek Pathfinder networks …
• Other names for the association strength probabilistic affinity index proximity index
Unit of analysisAuthors Journals Words/terms Web pages …
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Mapping techniques
Similarity measureDirect Indirect
Jaccard Cosine Association strength … Pearson
correlation Cosine …
Mapping techniqueDistance based Graph based
MDS VxOrd VOS … Pajek Pathfinder networks …
• Ordinal MDS in SPSS PROXSCAL• VxOrd (DrL)
VxOrd1: top 10 similarities, edge cutting (default settings) VxOrd2: all similarities, no edge cutting VxOrd3: top 10 similarities, no edge cutting
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Evaluation criteria
1. Quality of the mapsDoes a map provide a satisfactory representation of the data?
2. RobustnessMeasures the similarity between maps that have been constructed based on different samples drawn randomly from the same data set
3. EfficiencyMeasures the similarity between a map that has been constructed based on an entire data set and maps that have been constructed based on samples drawn randomly from that data set
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MDS – Jaccard index (journals)
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VxOrd1 – cosine (journals)
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VxOrd2 – cosine (journals)
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VxOrd3 – cosine (journals)
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VOS – association strength (journals)
1313
Comparison of maps (journals)
• MDS clearly performs worst, with no good separation between journals from different fields
• As is typical for MDS, journals are located more or less uniformly distributed within a circle
• VxOrd3 and VOS perform quite well, with a clear clustering of journals based on their field
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Robustness and efficiency (journals)
• MDS and VxOrd1 have a low robustness and efficiency• The other techniques do much better
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MDS – Jaccard index (terms)
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VxOrd1 – cosine (terms)
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VxOrd2 – cosine (terms)
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VxOrd3 – cosine (terms)
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VOS – association strength (terms)
2020
Comparison of maps (terms)
2121
Robustness and efficiency (terms)
2222
Conclusions
• No complete specification of VxOrd is available in the literature
MDS VxOrd VOS
Quality of the maps
locates objects more or less uniformly
distributed within a circle, with no clearly
separated clusters
produces attractive maps with a very clear clustering, but only if
appropriate parameter values are
chosen
produces satisfactory maps without the
need to choose any parameter values
Robustness and
efficiencylow
depends on parameter values and
data sethigh