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Bibliographic Coupling, Co-Citation and Mapping

Bibliographic Coupling, Co-Citation and Mapping. Peter Ingwersen Det Informationsvidenskabelige Akademi , Danmark University College, Oslo, Norway – 2010. Agenda. Bibliographic coupling Example Author co-citation Example, old vs. Newer (Dialog) Example, WoS, quick ’n dirty Maps.

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Bibliographic Coupling, Co-Citation and Mapping

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  1. Bibliographic Coupling, Co-Citation and Mapping Peter Ingwersen DetInformationsvidenskabeligeAkademi, Danmark University College, Oslo, Norway – 2010

  2. Agenda • Bibliographic coupling • Example • Author co-citation • Example, old vs. Newer (Dialog) • Example, WoS, quick ’n dirty • Maps 2008

  3. BIBLIOGRAPHIC COUPLING Doc 3 Doc 1 Doc 2 Ref X Ref.... .... Ref X Ref.... REF X Documents 1-3 are coupledby REF X… can be selected in WoS/Dialog, if X is known; s CR=X Doc 3 Ref X Ref.... 2008

  4. Example of bibliographic coupling • One article has 23 references on its reference list • Another has 54 references on its list • There are 4 references in common. Strength: 4 / (23 + 54 - 4) = 0.054 (max.=1) • Jaccard similarity measure • CA – CY/CU – CW could also be used 2008

  5. DOC A Ref X Ref Y DOC B Ref X Ref Y Doc X Doc Y CO-CITATION Documents X and Y areCO-CITEDTwiceon the reference lists of A and B (Doc. A is coupled bibliographically to Doc. B by X & Y) 2008

  6. Co-citation illustration:KNOWN CITATIONS – known cited documents Set Items Description S4 7 CA=JOSS PC(S)CY=1988(S)CW=NATURE S8 13 CA=FABIAN AC(S)CY=1987(S)CW=NATURE S9 6 S4 AND S8 COSINE: SIM = 6 / (71/2 * 131/2) = 0,63 JACCARD: SIM = 6 / (7 + 13 - 6) = 0,43 These are BINARY calculations (document level) WoS: can be done on cited author or cited work 2008

  7. Co-citation illustration:KNOWN AUTHORSHIPS – citing document level S1 279 CA=BELKIN NJ S2 86 CA=INGWERSEN P S3 955 CA=SALTON G S4 49 S1 AND S2 S5 70 S1 AND S3 S6 18 S2 AND S3 AUTHOR CO-CITATION SIMILARITY - 1990: 2008

  8. One creates an overlapmatrix 2008

  9. Co-citation illustration – Similarity matrix:KNOWN AUTHORSHIPS – Binary, citing document level – Jaccard & Cosine SIM(BELK/INGW): 49 / (279+86-49)= .16 Cosine: 49 /16.7 x 9.3 = .32 SIM(BELK/SAL): 70 / (279+955-70)=.06 Cosine: 70 /16.7 x 30.9 = .14 SIM(SAL/INGW): 18 / (955+86-18)=.02 Cosine: 18 /30.9 x 9.3 = .06 THIS WAS IN 1990 - WHAT IN 2000?? 2008

  10. One creates a similaritymatrix 2008

  11. At Item Level: Cosine and Jaccard OK: Similarity in a BINARY CONTEXT Ingwersen Belkin Agreement 2008

  12. Co-citation illustration:KNOWN AUTHORSHIPS - 1990-2000 Items Citations Name S1 541 933 CA=BELKIN NJ S2 258 382 CA=INGWERSEN P S3 13652417 CA=SALTON G S4 126 559 S1 AND S2 S5 175 680 S1 AND S3 S6 50 204 S2 AND S3 2008

  13. Co-citation illustration:KNOWN AUTHORSHIPS – Binary,citing document level; Jaccard & Cosine SIM(BELKIN/INGWERSEN): 126 / (541+258-126) = .19Cosine: 126 / 23.3 x 16 = .34 SIM(BELKIN/SALTON): 175 / (541+1365-175) = .10Cosine: 175 / 23.3 x 36.9 = .20 SIM(SALTON/INGWERSEN): 50 / (1365+258-50) = .03Cosine: 50 / 36.9 x 16 =.08 2008

  14. Co-citation illustration:KNOWN AUTHORSHIPS – non-binaryCitation level; Only Cosine (or Pearson) Similarity is calculated following this formular: Sim(b,i)= ∑(citb,d x citi,d) / √∑(citb,d²) x √∑(citi,d²) – e.g.: (3x2+4x1+3x0) / √(3²+4²+3²) x √(2²+1²+0)= 10 / √(9+16+9) x √(4+1) = 10 / √34 x √5= 10 / (5.8 x 2.34) = 10 / 13.64 = .73 For Belkin: 10 citations; Ingwersen: 3 citations; No. of documents co-citing: 2 – with (3x2 + 4x1 = 10 co-citations); No. of documents citing B: 3, with 10 citations in total No. of documents citing I: 2, with 3 citations in total 2008

  15. The trend 1978 - 2000 • The Belkin-Salton co-citation ratio has increased from 0.06 to 0.10 in the 90s • The Belkin-Ingwersen co-citation ratio has slightly increased, from 0.16 to 0.19 • Both pairs are thus closer to one another seen from colleagues’ views!! • 50 % of documents citing Ingwersen (126/258) co-cites him with Belkin after 1990. Up to 1990 this ratio was larger (49/86) = 57 %. 2008

  16. Co-occurrence applications • By co-citations: the perceived connexion between people: • Sharing Expertice • Check consistency by ageing measures of their work • By bibliographic coupling: people are connected by using the same work!! 2008

  17. Co-occurrence applications – 2 • Data mining in databases • Creation of maps of scientific domains • Demonstrate collaboration between: • People • Countries • Institutions • Topical areas • …. 2008

  18. Øvelse i co-citation • Update the Belkin, Salton, Ingwersen co-citation analysis for the period 2001-2011, by carrying it out at Document level (Binary analysis) via WoS. 2008

  19. WoS: Cited Ref Search 2008

  20. Ingwersen published 76 papers, cited 2008

  21. 153 items cited PI 165 times (2001-) 2008

  22. Belkin: 126 papers give 148 cites 2008

  23. Co-citations Belkin-Ingwersen 2001-11 2008

  24. The one record co-citing I & B 2008

  25. The two citations to Ingwersen 2008

  26. Limitations • WoS does sometimes NOT carry out all the analyses profoundly • With larger sets of citing papers (and citations) it is only possible to calculate the co-occurrence at DOKUMENT LEVEL 2008

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