Patterns of research collaboration in a digital library for economics

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Patterns of research collaboration in a digital
library for economics
Nisa Bakkalbasi Electronic Collections
Librarian Yale University
Thomas Krichel College of Information and
Computer Science Long Island University
ASIST 2006 Annual Meeting November 3-8,
2006 Austin, Texas
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Introduction

• This paper analyzes the patterns of authorships
  and incidence of collaborative relationships in a
  digital library for economics.
• We study co-authorship using social network
  analysis.

3
Background

• Studies on scientific productivity suffer from
  the multiple names that can be given to the same
  author, making identification difficult. For
  example
• Phillips, P. C. B
• Peter C. B. Phillips
• Peter Phillips
• For scientific collaboration studies, the issue
  becomes worse as the error in unique
  identification of one author extends across the
  whole network.

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Background

• To be precise, most collaboration studies study
  small networks
• All authors are known and can be identified by
  hand.
• Issues of computation are simple.
• This study examines a large co-authorship
  network where all authors are uniquely
  identified.
• The dataset comes from the RePEc digital library.

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RePEc Research Papers in Economics

• A digital library for economics and related
  disciplines.
• Provides access to 362,000 items of interest
  such as working papers, journal articles,
  software components, and instructional datasets.
• All RePEc data are freely available online.
• Data is contributed by academic departments,
  institutions involved in economics research (e.g.
  central banks), publishers, and individuals.
• A collaborative effort of hundreds of volunteers
  in 51 countries.

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RAS RePEc Author Service

• The RePEc author service is a site where authors
  registers and creates a professional profile.
• See http//ras.repec.org
• The author provides contact information,
  affiliation, and publications.
• The development of the software for the RePEc
  author service was supported by the Open Society
  Institute.
• For more information see http//acis.openlib.org.
  

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Record from the RAS database
Template-Type ReDIF-Person 1.0 Name-First
Christian Name-Last Zimmermann Name-Full
Christian Zimmermann Workplace-Organization
RePEcedideuctus Email christian.zimmermann_at_ucon
n.edu Homepage http//ideas.repec.org/zimm/ Autho
r-Paper repeccrecrefwp33 Author-Paper
repecmtlmontde2000-05 Author-Software
repecdgeqmrbcd99 Author-Software
repecdgeqmrbcd97 Author-Paper
repecuctuconnp2005-01 Author-Article
repeceeejceconv33y2005i1p88-106 Author-A
rticle repeceeejmacrov26y2004i4p637-659
Author-Paper repecscescecf5372 Author-Paper
repecredsed005561 Short-Id pzi1 Handle
repecper1964-12-14christian_zimmermann Last-Log
in-Date 2005-11-21 152520 -0500 Registered-Date
2004-02-29 173609 0600
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Screenshot of a web page that renders this data
on the web
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How complete is RAS?

• RAS has been in use since 1999.
• When we did the study
• 1/3 papers had been claimed by at least one
  registered author.
• 1/4 authorships are covered in RAS.
• RAS expands over time, but RePEc expands too, so
  these ratios only move up slowly.
• We conjecture that there is a tendency for
  prolific authors to register.

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Distribution of the number of authors per paper
in RePEc and RAS
Number of authors Number of papers RePEc R
AS 1 180,716 (49.91) 99,562
(80.00) 2 129,638 (35.80) 22,315 (17.93) 3
42,427 (11.72) 2,425 (1.95) 4 7,021
(1.94) 130 (0.10) 5 1,338 (0.37)
9 (0.01) 6 425 (0.12) 4
(0.00) 7 193 (0.05) 1 (0.00) ?
8 99 (0.03) 1 (0.00)
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Summary statistics for RAS registrants
of RAS registrants 12,381 of registrants
who did not claim a paper 3,715 of
registrants who claim at least one paper
8,666 of authorships
152,072 Average number of papers/author 17.55
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Authors ranked according to the number of
co-authors
Rank Author Co-authors Papers 1 Randall
Wright 27 106 2 Joseph Stiglitz 26 320 3 Clive
Granger 25 165 4 James Stock 23 111 5 Pierre
Chiappori 23 91 6 Martin Feldstein 22 259 7 Phi
lip Franses 22 163 8 Robert Hubbard 22 116 9 F
rancis Diebold 21 189 10 Stephen
Jenkins 21 138
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Frequency distribution of authors by number of
documents
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Summary statistics for RAS authors and
co-authorship networks
Number of authorships by co-authors 137,550 Numb
er of authors with at least one
co-author 5,661 Number of authorships with at
least one co-author 109,924 Average number of
collaborators/co-author 2.05 Size of the
largest component 4,659 Number of
components 382 Network diameter 22
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Component size distribution
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Degree centrality distribution
Only a few authors have a high degree of
connection while many others have a low degree.
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Authors ranked according to centrality measure
RankDegree Betweenness Closeness 1 Randall
Wright 54 Joseph Stiglitz 903758.86 Joseph
Stiglitz 4.8199 2 Joseph Stiglitz 52 F.
Schiantarelli 700949.47 Olivier Blanchard 4.8952
3 Clive Granger 50 J. von Hagen 699927.26 James
Stock 4.9594 4 P. Chiappori 46 Costas
Meghir 626284.35 F. Schiantarelli 4.9972 5 James
Stock 46 Clive Granger 587076.57 Martin
Feldstein 5.0004 6 M. Feldstein 44 Gert
Wagner 579692.04 J. von Hagen 5.0453 7 Philip
Franses 44 Mark Taylor 551873.68 Costas
Meghir 5.0459 8 R. Hubbard 44 O.
Blanchard 541855.20 B. Eichengreen 5.0711 9 F.
Diebold 42 Pierre Chiappori 530045.41 Marcus
Miller 5.0805 10 S. Jenkins 42 K.
Zimmermann 504285.85 Alison Booth 5.0893
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Conclusions

• Authors who have written a large number of
  papers tend to register with RAS.
• The 80/20 Rule (i.e., 80 of the information
  productivity is generated by 20 of the
  information resources), does not apply to RAS
  authors.
• RAS registrants appear to have a broad range of
  coauthors, with most having only a few coauthors,
  whereas a few having many.
• RAS population is made up of highly active
  academics.

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Further Work

• RePEc also identifies institutions.
• Therefore work on institutional collaboration
  can be done quite easily.
• It is also possible to compute various rankings
  of
• authors
• institutions
• journals
• using citation and download data.

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Questions, comments nisa.bakkalbasi_at_yale.edu