The Network Structure of Sociology Production

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The Network Structure of Sociology Production
James Moody Duke University Stanford University
Colloquium March, 2007
2
Introduction

• Outline
• Networks Science Two Questions 4 networks
• How do scientific fields evolve?
• Where do good ideas come from?
• Data Sources Methods
• Results
• Where does sociology fit? Journal co-citation
  networks
• What do sociologists study? Topic networks
• Who produces sociology? Social science
  collaboration networks
• Discussion

3
Networks Science Two Questions 4 networks
"Science, carved up into a host of detailed
studies that have no link with one another, no
longer forms a solid whole." Durkheim, 1933
4
Networks Science Two Questions 4 networks

• The extent to which science is carved up into a
  host of detailed studies that have no link with
  one another is a question of network cohesion
• A fractured discipline will be dominated by tight
  clusters based on specific research problems,
  while an integrated discipline will have strong
  connections bridging research problems.

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Networks Science Two Questions 4 networks

• How do scientific fields evolve?
• Is there a coherent logic to the ebb and flow of
  topics studied?
• How does the success or failure of ideas depend
  on the social community in which it is embedded?
• (How) Does the evidentiary basis of a field shape
  its logic of discovery?
• The descriptive answer is given by mapping the
  field in network space.
• The analytic answer will come by modeling the
  emergence, growth and decline of scientific
  subfields.

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Networks Science Two Questions 4 networks

• 2) Where do good ideas come from?
• What is a good idea?
• Ideas that change a scientific field. Indexed by
  (a) citations and (b) the relevant topography of
  the networks within which the idea was originally
  embedded. Ideas are not inherently good they are
  recognized as good by their effect on a field.
• How do disciplines produce new ideas?
• Intersection ? Good ideas are produced by
  combining ideas of others in unique ways (Burt)
• Development ? Good ideas arise naturally from
  either the progressive error reduction process
  of good normal science (Popper) or the accepted
  practices of a scientific community (Crane).
• Peer Influence Recognition ? Any idea is a
  good idea if others think so, and thinking so is
  influenced by the network. (Gould).
• Resource competition ? Search for prestige
  conditioned by organizational structure (Fuchs)
• Will model this by examining how citations are
  affected by field dynamics (and vice versa).

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Networks Science Two Questions 4
networks Theoretical approaches to scientific
development

• Normal Science, accumulation revolution
• Science is problem driven evidence based
• Consensus emerges through a competition of ideas
  against data
• (though lab ethnography repeatedly shows that
  consensus is often more socially constructed than
  evidentiary)
• Scientific Star systems reward prior success,
  and stars shape research agendas
• Boundary Specification Science as a profession
• -Motivated by prestige competition for
  resources
• -Competition will lead to both vanquishing and
  niche filling
• Disciplinary identity coherence become a key
  issue
• Contested fields lead to chaotic outcomes
  (Abbott 2001)

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Networks Science Two Questions 4
networks Theoretical approaches to scientific
development

• Invisible Colleges
• Informal communities create acceptable scientific
  standards
• Boundaries are defined socially through
  interaction
• Scientific (social) Movements
• Combination of many of these ideas under a social
  movement frame
• Coherence becomes a framing grievance issue
  used to shape resource allocation

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Networks Science Two Questions 4
networks Theoretical approaches to scientific
development
We are thus left with multiple action frames to
guide our understanding Truth Ideas run their
error-reduction course (Popper) Prestige Actors
seek the greatest visibility (Merton) Resource
competition To the victor goes the spoils
Fuchs Boundary Protection (Gieryn ) Fractal
Development (Abbott) Community Influence (SSK
Collins, etc) Peer magnification (Gould) Power
(JL Martin) For entire fields, these mechanisms
are largely unknown and underspecified. ? Need
to extend beyond particular lab studies ? Take a
large-scale Satellite view of science
dynamics ? Link action frames to specific
patterns in 4 science networks
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Networks Science Two Questions 4
networks Theoretical approaches to scientific
development

• Four relevant networks
• Citation networks a direct trace of scientific
  recognition production
• Topic networks clusters of scientific products
  related to the same subject
• Collaboration networks invisible communities
  of social interaction that produces scientific
  products
• Research Communities People linked through
  common research topics (Substantively a
  derivative of 2 3)

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Networks Science Two Questions 4 networks
Scientific Environments
Evidentiary Basis How do we array disciplines
with respect to evidence? Two Dimensions
Objectivity Control Objectivity is taken from
Popper The extent to which a given knowledge
claim is independent of the knower. Control
refers to the ability of scientists to directly
manipulate the object of study. Lab Science
with complete ability to control apparatus (and
thus environment) represents the strongest
ability, while observation represents the
other. Cases Chemistry (Lab Science High
Objectivity High Control) Paleontolgoy
(Field Science High Objectivity Low
Control) Sociology (Social Science Moderate
Objectivity Low Control) Cultural
Anthropology (Low Objectivity Low
Control) This approach is very similar to Fuchs
(1993)
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Networks Science Two Questions 4 networks
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Networks Science Two Questions 4
networks Focusing on Sociology as a current case

• The field of sociology can thus be thought of as
  the intersection of multiple networks.
• The shape of these networks differs across scales
  and over time.
• - Differences between local and global visions
  of the network shape our perceptions of
  scientific coherence.
• We tend to perceive coherence in our own
  specialty fields and incoherence for the entire
  discipline.
• A globally federated structure, that cannot
  easily exclude empirical topics, might still be
  socially coherent if scientific mixing cross-cuts
  empirical problems.
• We can see this structure by examining these 4
  networks at large scale and over time.

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Data Sources

• Citation Networks
• Compiled from the ISI web of science Journal
  citation tables
• Covers 1681 social science journals indexed in
  2003
• Will eventually
• -fill this series from 1950 to present across all
  fields.
• -Add a sample of paper-level citations to model
  performance.
• Topic Collaboration Networks (for Sociology)
• Compiled from Sociological Abstracts
• 281,163 papers published between 1963 and 1999
• A sub-sample of sociology only papers published
  in a select set of non-specialty sociology
  journals ? 35 of the total (100K)
• Contains information on title, abstract,
  keywords, author(s), tables, journal citation
• Will use similar indexes for Chemistry, Geology
  and Lit Crit

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Where does sociology fit?

• Perennial debates over the existence of a
  theoretical core
• Rapid growth in the internal diversity of topics
  sociologist study

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Where does sociology fit?

• Perennial debates over the existence of a
  theoretical core
• Rapid growth in the number of journals relevant
  to sociologists

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Where does sociology fit?

• This growth diversity has been seen as evidence
  for the ultimate emptiness of sociology as a
  scientific discipline.
• But disciplines are shaped by the connections
  between ideas, not the number of ideas.
• That is, we recognize fields by who they speak to
  as much as by what they speak about.
• The clearest empirical trace of this
  communication is citation.
• Disciplines can then be defined as clusters of
  work that speak more to each other than to anyone
  else, which we trace with co-citation networks.

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Where does sociology fit?
Building co-citation networks
Links in a co-citation network are constructed by
measuring how similar each journal is to every
other journal. Similarity is gauged by
correlating the pattern of citations received by
each journals from every other journal.
Comparing across columns tells us whether the two
journals are recognized by others as similar.
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Where does sociology fit?
Building co-citation networks
AJS ASR AER JER AJS ASR
AER . . . JER
Links in a co-citation network are constructed by
measuring how similar each journal is to every
other journal. Similarity is gauged by
correlating the pattern of citations received by
each journals from every other journal.
1.0
High
1.0
1.0
Med
Low
High
Low
Low
1.0
This create a valued network of ties between two
journals. I use a cosine similarity score
developed in bibliometrics, selected for those
with ties gt 0.45 at sharing at least 2 of
their citation volume. Source Loet Leydesdorff
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Where does sociology fit?
Economics co-citation similarity network
Density 0.197 N152 Isolates (not shown) 5
Node size proportional to log(degree)
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Where does sociology fit?
Political Science co-citation similarity network
Density 0.160 N69 Isolates (not shown) 10
Node size proportional to log(degree)
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Where does sociology fit?
Sociology co-citation similarity network
Density 0.140 N69 Isolates 7
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Where does sociology fit?
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Where does sociology fit?
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Where does sociology fit?
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Where does sociology fit?

• Sociology fits at the center of the social
  sciences. We are not as internally cohesive as
  Economics or Law, but more so than many
  (anthropology, allied health fields).
• This represents a tradeoff. We have traded
  unique dominance of a topic (markets, politics,
  mind, space) for diversity thus centrality.
• Sociology is an interstitial discipline (Abbott,
  2004) in at least two-senses
• There is no content topic we can reasonably
  exclude
• We pull together, and generate, the ideas and
  topics covered by specialty disciplines.
• This makes us uniquely positioned to provide
  insights on many different empirical questions.
  How have the topics sociologists study shifted
  over time?

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How does this look in the Physical Sciences?
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What do sociologists study?

• How do we capture the internal organization of
  research problems?
• Could use paper-level citation networks (see
  Hargens 2000), but data are difficult expensive
  to obtain for large-scale networks.
• Can examine the network of papers formed by the
  topics they write about.
• Directly taps scientific content
• Purely endogenous creation of topics that allows
  new topic areas to emerge and old ones to die
  over time
• Tractability data can be extracted from
  information held in Sociological Abstracts
• Multiple levels
• Coarse grained? Focus solely on keywords (Light
  2005)
• Fine grained ? Use all information available
  (title, abstract, keywords)

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What do sociologists study?
A fine grained view

• Data Selection Manipulation
• Index entries contain title, abstract and
  keywords that summarize the papers content.
• Sample all papers indexed within four 3-year
  windows between 1970 and 1999.
• Construct a paper by word matrix, where the
  ij cell lists how many times word i is used to
  describe paper j.
• Word set is stemmed to get at root words
• A stop-list is used to minimize inclusion of
  low-information content words (the and is
  etc.) or words commonly found in the data source
  (Tables Figure References)
• Construct a network by linking the most highly
  correlated papers
• Use correlation of 0.40 or better
• Ties are treated as valued in the network analyses

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What do sociologists study?
A fine grained view

• Analysis Presentation General approach is
  quantitatively inductive
• - Construct a low-dimensional map of the network,
  using contour sociograms. These allow for full
  information in the network structure.
• Use cluster analysis to identify distinct topics
• Use a variant of Moodys RNM algorithm to cluster
  the network
• This clustering routine
• (a) is efficient Allows clustering on 10s of
  thousands of nodes
• (b) automatically specifies the optimal number
  of clusters
• (c) allows that some cases can fall between
  clusters
• I set a minimum cluster size of 12 papers
  published over the 3-year window.
• Evaluate the clustered papers for content and
  label the maps.

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What do sociologists study?
A fine grained view
Analysis Presentation General approach is
quantitatively inductive Compare the maps over
time qualitatively, looking for general changes
in the frequency alliance of topics. Examine
shifts in structural indicators of the extent of
clustering cluster size distributions.
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What do sociologists study?
A fine grained view
Example One-step neighborhood of More
information, better jobs?
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What do sociologists study?
A fine grained view
Example One-step neighborhood of More
information, better jobs?
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What do sociologists study?
A fine grained view Content (all journals)
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What do sociologists study?
A fine grained view Content (all journals)
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What do sociologists study?
A fine grained view Content (all journals)
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What do sociologists study?
A fine grained view Content (all journals)
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What do sociologists study?
A fine grained view Content (all journals)

• The cluster content of the topic network has
  evolved slowly
• Some clearly central specialties have remained
  prominent over the entire period. This includes
  larger areas such as
• Class Stratification
• Race Ethnicity
• Education
• Gender (Strongest from 1980s on)
• Family (Strongest from the 1980s on)
• Crime
• As well as clearly distinct, though numerically
  smaller bodies of research related to
• Suicide
• Sociology of Science, Technology Reflexive
  sociology
• Unions

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What do sociologists study?
A fine grained view Content (all journals)

• The cluster content of the topic network has
  evolved slowly
• The clearest change has been the rapid growth of
  social research on health.
• Dominated by a very large body of research
  related to HIV/AIDS
• Other areas of relative growth include
• Family topics were most prominent in the 1980s
• A strong presence of research on sex sexuality
  emerged in the 1980s and 90s
• Relative declines have come in areas such as
• Groups
• Interaction
• Radical studies
• Elite studies
• Summary A move away from basic social processes
  toward studying social problems, with a growing
  uniqueness of theory method

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What do sociologists study?
A fine grained view (all journals)
Cluster Size Distribution
(hidden)
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What do sociologists study?
A fine grained view Content (Restricted Sample)
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What do sociologists study?
A fine grained view Content (Restricted Sample)
43
What do sociologists study?
A fine grained view Content (Restricted Sample)
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What do sociologists study?
A fine grained view Content (Restricted Sample)
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What do sociologists study?
A fine grained view Content (Restricted Sample)

• The cluster content of the restricted topic
  network has evolved similarly to the wider social
  science field
• The subfield structure is less dominated by the
  purely applied work on HIV/AIDS in the 90s, but
  there is a still a clear association of topics
  around sexuality, health and AIDS.
• Health, Family, Education, Gender, and Race are
  always prominent and large.
• The relative prominence of reflexive sociology
  is much higher
• These topics cannot be published elsewhere, and
  the resulting tight cluster looks proportionately
  larger in the smaller sample.

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What do sociologists study?
A fine grained view (Core Soc journals)
Cluster Size Distribution
Hidden
47
What do sociologists study?
A fine grained view Content
We can measure the degree of consensus in words
used to describe papers with
C S pi2
Where pi is the proportion of times word i is used
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What do sociologists study?
A fine grained view Content
Word Consensus Scores 1970 - 1999
Soc Only
C (x 100)
All SA Journals
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What do sociologists study?
A fine grained view (Core Soc)
Proportion of papers falling inside a cluster
Total
Cn gt 12
Restricted
Total
Cn gt 100
Restricted
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What do sociologists study?
A fine grained view (Core Soc journals)

• Largest Clusters
• 1970
• Culture (126,3.7)
• Organizations (134,4.0)
• Race (Black) (137,4.1)
• Students (137,4.1)
• Community (138,4.1)
• 1980
• Education (167,2.6)
• Sex Roles (182,2.9)
• Research (191,3.1)
• Sociology (225,3.6)
• Family (273,4.3)

• 1990
• Women (246,2.7)
• Schools (259,2.8)
• Sociology (427,3.6)
• Health (427,4.65)
• Family (273,4.3)
• 1997
• Children (302, 2.89)
• Women (346, 3.32)
• Critical Sociology (359, 3.32)
• Education (380, 3.64)
• Health (714, 6.8)

Hidden
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What do sociologists study?
A fine grained view
We can measure the extent that ties fall within
clusters with the modularity score
Where s indexes clusters in the network ls is
the number of lines in cluster s ds is the sum
of the degrees of s L is the total number of
lines
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What do sociologists study?
A fine grained view
Network Modularity 1970 - 1999
All SA Journals
Soc Only
Modularity Score
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What do sociologists study?
A fine grained view
Proportion of all ties within cluster 1970 - 1999
In-cluster ties / Total ties
All Journals
Soc Only
Hidden
54
What do sociologists study?
A fine grained view
Number of Clusters 1970 - 1999
All Journals
Total Number of Clusters
Soc Only
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What do sociologists study?
A fine grained view
Mean Cluster Size 1970 - 1999
All Journals
Soc Only
Mean Size of Clusters
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What do sociologists study?
A fine grained view

• The cluster structure of the topic network
• The vast majority of papers can be assigned to
  clear clusters, with slight growth in this
  proportion over time.
• The number of clusters has increased rapidly,
  though slightly slower within core sociology than
  in the broader field of social science.
• There has been significant growth in the tails of
  the distribution the size distribution is more
  skewed in later periods.
• The modularity of the network has increased over
  time, though most of this change is between the
  1970 and 1980 periods.
• This meshes with our intuition of separate
  worlds in the social sciences larger, more
  distinct topical production of science work.

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What do sociologists study?
A fine grained view

• Next steps
• Build a continuous moving window to fill in the
  dates from 1960 to 2005.
• Link clusters across time periods, so we can
  track exactly the relative growth and decline of
  each subfield.
• Model this growth as a function of connections to
  other fields, author composition and disciplinary
  environment.
• Build this networks dual scientists connected
  through topics.

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What do sociologists study?

• A clustered topic structure focused strongly on
  practical problem solving has a hint of
  Durkheims concern Is there any integration
  across these topic clusters?
• We shouldnt jump too quickly to the fractured
  conclusion
• Topic clusters are formed from papers, and papers
  typically have well encapsulated ideas. They
  have a small maximum digestible unit
• Scientific integration is really about how
  scientists bridge these multiple topics.
• If authors write and collaborate across these
  topics, ideas can quickly disseminate as well.
• What is the structure of the collaboration graph
  if this is highly clustered it would signal
  potential fragmentation ? Who produces sociology?

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Who produces sociology?

• Science is typically produced through
  collaboration, both formally and informally
  (Crane 1972, Crane Small 2000, Friedkin 1998).
• The best empirical trace of collaboration for
  large communities of science is coauthorship.
• Misses the less intense collaborations recognized
  in acknowledgements, discussions, colleagues
  reading each others work
• But should provide the strongest test of a
  fractionalization hypothesis, since the set of
  people we write with should be more like us than
  the set of people we have lunch with or discuss
  work with informally.
• There are differences across subfields in formal
  collaboration rates, which, if anything, should
  magnify the extent of observed fragmentation.

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Who produces sociology?
Coauthorship Trends in Sociology Sociological
Abstracts and ASR
0.75
0.6
0.45
Proportion of papers with gt1 author
0.3
Sociological Abstracts
ASR
0.15
0
1930
1940
1950
1960
1970
1980
1990
2000
Year
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Who produces sociology?
Distribution of Coauthorship Across
Journals Sociological Abstracts, 1963-1999
Child Development
1
0.8
Soc. Forces
J. Health Soc. Beh.
ASR
0.6
Proportion of papers w. gt1 author
AJS
J.Am. Statistical A.
0.4
Atca Politica
Soc. Theory
Signs
0.2
J. Soc. History
0
0
100
200
300
400
500
600
700
800
900
1000
1100
Coauthorship Rank
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Who produces sociology?
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Who produces sociology?
Construct a collaboration network by assigning an
edge between any pair of people who coauthored a
paper together.
Example Paths 3-steps from Stan Wasserman
N361
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Who produces sociology?
Construct a collaboration network by assigning an
edge between any pair of people who coauthored a
paper together.
Example Paths 3-steps from Stan Wasserman
N361
Node size proportional to log of degree
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Who produces sociology?
The simplest summary test for a fragmented
network is to measure the extent of clustering in
the network. Watts work on the small-world
problem suggests that if the collaboration
network is a small world network it might be
fractured.
CLarge, L is Small SW Graphs

• High relative probability that a nodes contacts
  are connected to each other.
• Small relative average distance between nodes

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Who produces sociology?
In a highly clustered, ordered network, a single
random connection will create a shortcut that
lowers L dramatically
Watts demonstrates that Small world properties
can occur in graphs with a surprisingly small
number of shortcuts
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Who produces sociology?
Locally clustered graphs are a good model for
coauthorship when there are many authors on a
paper.
Paper 1
Paper 2
Paper 3
Paper 4
Paper 5
Newman (2001) finds that coauthorship among
natural scientists fits a small world model.
I test this model on the sociology coauthorship
network, using all authors from 1963 1999.
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Who produces sociology?
Observed
Random
Clustering
0.194
0.206
9.81
7.57
Distance
The sociology network is less clustered than
would be expected by chance and somewhat longer
overall distances. This suggests that it does
not have a small-world structure.
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Who produces sociology?
The network has a broad Core-periphery structure
(68,923)
59,866
38,823
29,462 Bicomponent
Component
Unconnected
Structurally Isolated
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Who produces sociology?
Largest Bicomponent, g 29,462
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Who produces sociology?
Internal Structure of the Coauthorship Core
Health
General Sociology
72
Who produces sociology?
73
Who produces sociology?
Internal Structure of the largest bicomponent
Group 1
Group 2
Size
3667
987
In-group / out- group ties
3.24
2.86
male
67
52
Years in discipline
8.46
4.67
Number of co-authored publications
5.32
3.24
74
Who produces sociology?
Internal Structure of the largest bicomponent
75
Who produces sociology?
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Who produces sociology?

• Strong specialty effects for ever-coauthored
• Unlikely
• History Theory
• Sociology of Knowledge
• Radical / Marxist Sociology
• Feminist / Gender Studies
• Likely
• Social psychology
• Family
• Health Medicine
• Social Problems
• Social Welfare

77
Who produces sociology?

• Weak specialty effects for network embeddedness
• Large number of coauthors increases embeddedness
• Large number of people on any given paper
  decreases embeddedness

78
Who produces sociology?
Graph Connectivity, Cumulative 1963 - 1999
0.6
in Giant Component
0.5
0.4
of connected in bicomponent
Percent
0.3
0.2
0.1
0
1965
1970
1975
1980
1985
1990
1995
2000
Years (1963 - date)
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Who produces sociology?
0.4
2.25
Evolution of Network Cohesion 5-year moving
window
0.35
2.2
0.3
0.25
2.15
0.2
Percent
Connectivity
2.1
0.15
0.1
Connectivity
2.05
Bicomponent
0.05
Component
0
2
1975
1980
1985
1990
1995
2000
Year
80
Summary discussion

• Social Science Citation Structure
• Economics, Law, Psychology, Business/Management,
  Linguistics are most cohesive
• The are also peripheral in that they speak to a
  relatively limited set of problems
• Sociology is at least as cohesive as Political
  Science, and more cohesive than fields such as
  Anthropology, Social Work, Education or allied
  health fields that all have more limited
  empirical domains
• Our position represents a tradeoff between
  internal cohesion and external centrality.

81
Summary discussion

• Scientific Topic Network
• Big-Picture A general progression towards
  problem solving and the specialization of work on
  theory methods (Light 2005).
• Fine-grained structure
• A federated topic structure that has largely
  retained that form since the 1970s, though there
  have been shifts in substantive topics.
• Key content areas have remained largely constant
• Race, Family, Class, Gender, Science, and Health
• A decrease in focus on general foundation
  problems
• Group structure, community, interaction
• An increase in work on social problems
• Health HIV/AIDS -related topics
• Some (minor) evidence for greater homogeneity in
  topics discussed

82
Summary discussion

• Scientific Collaboration Network
• The networks is not divided into small
  research-area based clusters.
• There is no partition that strongly separates
  scientists.
• This has to imply that authors bridge topic
  clusters.
• This is good for social cohesion, and probably
  good for theoretical cohesion.
• Caveat There is evidence for a division based
  on research method, with largely quantitative
  work more likely to be coauthored, though there
  is no such simple division in the topics network.

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Summary discussion

• Combined, these models suggest a discipline that
  is integrated socially and locally cohesive
  topically.
• Discipline-wide integration will likely only
  increase as pressures for collaboration push more
  scientists to work together across topics.
• However, the perception of disintegration will
  likely continue
• because most of us are only exposed outside our
  areas by work that appears in the general
  journals.
• But almost all of the topical cohesion is due to
  normal science work occurring in specialty
  journals.

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