Social Network Analysis

Social Network Analysis, TT 2012.

Course providers:

Prof Tom A.B. Snijders
Department of Politics and International Relations, Department of Statistics.
(tom.snijders "at" nuffield.ox.ac.uk; http://www.stats.ox.ac.uk/~snijders/).
Dr Felix Reed-Tsochas
Saïd Business School
(felix.reed-tsochas "at" sbs.ox.ac.uk; http://www.sbs.ox.ac.uk/research/people/Pages/FelixReed-Tsochas.aspx)

Overview

This course is an introduction to social network analysis, with a focus on modelling. The aim is to give students an overview of research questions connected to social networks, and of descriptive measures, models, and methods of analysis that can be used to analyze empirical social network data.

Objectives

Upon completion of the course the students should:

be able to formulate meaningful research questions concerning social network analysis;
have ideas about how to gather relevant network data, and some of the associated questions and problems;
have access to a variety of descriptive measures for networks and software to calculate them, and have the ability to interpret the results;
be able to formulate agent-based models which from local behaviour of agents can generate networks with diverse global structures;
know how to conduct computer simulations to analyze properties of such models;
be able to specify stochastic actor-oriented models for analyzing dynamics of panel observations of networks, and of networks and individual behaviour;
know how to execute and interpret analysis of an empirical longitudinal network data set by stochastic actor-oriented models.

Meeting Schedule and handouts

Location: Manor Road Building.

Time schedule for TT 2012.
(Teachers indicated by FRS and TS.)

Week 1

Thursday, April 26, 2.00-4.00 pm, FRT, seminar room B.
Graphs and matrix representations.
Friday, April 27, 2.00-4.00 pm, IT room.
Introduction to R by Dr Tak Wing Chan.
(important unless you already have a good working knowledge of R).
Week 2
Thursday, May 3, 2.00-4.00 pm, TS, seminar room B.
- Handout.
- Example 1:
  F.R. Pitts (1979), The medieval trade network of Russia revisited. Social Networks, 1, 285-292.
- Example 2:
  Marc Flandreau and Clemens Jobst, "The Ties that Divide: A Network Analysis of the International Monetary System, 1890-1910", The Journal of Economic History, 65 (2005), 977-1007.
- Example 3:
  Peter S. Bearman, James Moody, and Kate Stovel (2004), Chains of Affection: The Structure of Adolescent Romantic and Sexual Networks. The American Journal of Sociology, 110, 44-91.
- Structural equivalence, regular equivalence. Block modeling.
  Handout: Equivalences and blockmodeling.
- Anuška Ferligoj, Vladimir Batagelj, Andrej Mrvar, Course on blockmodeling, see pages 8-16.
- Another example, not treated:
  John F. Padgett and Christopher K. Ansell (1993), Robust Action and the Rise of the Medici, 1400-1434. The American Journal of Sociology, 98, 1259-1319.
Thursday, May 3, 4.00-6.00 pm, TS, IT room (computer class).
- R script sna_intro.r for first IT lab session.
  directory with data files and Lazega lawyers data description.
- Rscript01DataFormat.R with some basic information about R, networks, data formats etc;
  with an example data file arclistdata.dat.
- s50 data set, a 50-actor excerpt from the Teenage Friends and Lifestyle Study data set of West et al.: description and data set (longitudinal, 3 waves, networks and behaviour);
Week 3
Thursday, May 10, 2.00-4.00 pm, FRT, seminar room B.
Linking local and global properties.
Week 4
Tuesday, May 15, 5.00-7.00 pm, TS, seminar room A.
Wednesday, May 16, 5.00-7.00 pm, TS, seminar room B.

Topic to be treated:

Local structure in social networks.
Literature for this topic:
- Transitivity and Triads: download lecture as handout
  Transitivity and Triads: download lecture as transparencies
Statistical analysis of network dynamics.
Network panel data.
Stochastic actor-oriented models for network dynamics.
Statistical inference for simulation models.
Studies of networks and behaviour.
Selection and influence.
Literature for this topic:
- Introduction to Stochastic actor-oriented models as slides or as handout.
- Snijders, T.A.B., Steglich, C.E.G., and van de Bunt, G.G., (2010). Introduction to actor-based models for network dynamics. Social Networks, 32, 44-60.

Week 5

Thursday, May 24, 2.00-4.00 pm, FRT, seminar room B.
Week 6
Tuesday, May 29, 9.00-11.00 am, TS, seminar room B.
Thursday, May 31, 9.00-11.00 am, TS, IT room (computer class).

Computer software

The course will use appropriate packages of R. This will include the packages sna, igraph, and RSiena. There will be a crash course in R in week 1 of Trinity Term, offered by the Department of Sociology.

Assessment

The students will be assessed by means of an essay of at most 5000 words (advised length 3000-4000 words) which must be submitted before the end of week 9 of Trinity Term. The essay will have to contain an analysis of observed or simulated network data. The topic should be agreed upon by the student and one of the course instructors before or within week 6.

Practice assignment

An assignment will be given to the students in week 4, to be completed before the end of week 6. This will be an analysis of an observed network data set or the exploration of a network simulation model.

The instructors will provide a variety of questions concerning data sets and simulation models, so that for each different question for a data set or model, there will be no more than two students working on it.

This assignment will be for feedback purposes only, and students are allowed to collaborate. The assignment should be fulfilled by an essay of 1000-2500 words. The assignments will be returned, with comments from the instructors, in week 6 or early week 7.

Topics

The following is a provisional list of topics and materials; this is still undergoing changes.

The first topic is broad and general, and will be discussed in all of week 2.
General readings
- Stephen P. Borgatti, Ajay Mehra, Daniel J. Brass, Giuseppe Labianca, Network Analysis in the Social Sciences, Science 323, 892-895 (2009).
- Introduction to social network methods (2005), a free online introductory textbook on social network analysis by Robert Hanneman and Mark Riddle.
  There is also a pdf version of this text.
Items treated
- The structure and collection of social network data.
  Egocentric and whole networks; network boundary problem; network surveys and name generators; archival data; experiments.
- Basic concepts of graph theory and representation of networks (see handout week 1).
- Visualization of networks.
- Overview of some network theories motivating the measures treated next.
  Stephen P. Borgatti and Virginie Lopez-Kidwell, Network Theory.
  Strength of weak ties, cohesion and brokerage, social capital.
- Centrality.
  Degree, betweenness, closeness, eigenvector.
  See Chapter 10 of Hanneman & Riddle..
- Cohesion.
  
  Density, fragmentation, cliques, k-plex, k-core, modularity.
  See Chapter 11 of Hanneman & Riddle..
- Brokerage.
  Bridges, structural holes.
  See Chapter 9 of Hanneman & Riddle..
- Positions and equivalence.
Hands-on computer class introducing R packages sna and igraph.
Micro-models and macro-properties.
handout.
Network properties at local and global scales.
Affiliation networks.
Two-mode networks and their one-mode projection.
Empirical evidence for small worlds.
Milgram's experiment and its e-mail implementation by Dodds, Muhamad and Watts..
Some local and global network properties.
Transitivity, clustering coefficients and geodesic paths.
The Watts-Strogatz model.
Ordered lattices and random graphs, building a tuneable model with rewiring, search problems.
Small worlds and innovation.
Analysing co-inventor networks
Experimental small worlds.
Controlling network structure in laboratory experiments.
Power laws.
handout.
General properties and empirical evidence, goodness of fit, parameter estimation.
Preferential attachment.
Growth models for scale-free networks, sensitivity to initial conditions and specifications, variants of linear preferential attachment.
Other logics of attachment.
Alternative models for network growth, empirical evidence for collaborations between organisations in biotech.
Network contraction.
Reversing attachment models, rules for removing vertices and edges.
Co-authorship networks.
Growth rules for co-authorship networks, the structure of collaboration.
Stochastic and agent-based models.
Modelling team formation, network structure and performance.
Statistical analysis of network dynamics.
Network panel data.
Stochastic actor-oriented models for network dynamics.
Statistical inference for simulation models.
Studies of networks and behaviour.
Selection and influence.
Literature for this topic:
- Introduction to Stochastic actor-oriented models.
  The social science students may focus on the less mathematical part of this introduction!
- Snijders, T.A.B., Steglich, C.E.G., and van de Bunt, G.G., (2010). Introduction to actor-based models for network dynamics. Social Networks, 32, 44-60.
Hands-on computer class introducing the package RSiena.
- Ripley, R., and Snijders, T.A.B. (2012) Manual for SIENA version 4.0. University of Oxford: Department of Statistics and Nuffield College.
- Rscript01DataFormat.R with some basic information about R, networks, data formats etc;
  with an example data file arclistdata.dat.
- s50 data set, a 50-actor excerpt from the Teenage Friends and Lifestyle Study data set of West et al.: description and data set (longitudinal, 3 waves, networks and behaviour);
- Rscript02SienaVariableFormat.R for how to specify data as variables in RSiena, and specify the model;
- Rscript03SienaRunModel.R for how to carry out the estimation and look at the results;
- Rscript04SienaBehaviour.R for how to specify models for dynamics of networks and behaviour;
- van de Bunt students data description and data set (longitudinal)
- Assignment about homophily and transitivity, using one of the school classes of Andrea Knecht;
- RscriptASNAassignement.R
  Script for the assignment.
- description and data set of the data (longitudinal, networks and behavior) collected by Andrea Knecht.
Model specification and interpretation of stochastic actor-oriented models for network dynamics.
Workshop on students' proposals for essay topics and plans.
Pointers to other topics, methods, studies, and software.
Continued workshop on students' proposals for essay topics and plans.

Literature (indicative / provisional)

- Borgatti, S.P. and Kidwell, V. In Press. "Network Theorizing". In Carrington, P. and Scott, J. (eds) The Sage Handbook of Social Network Analysis. Sage Publications
- Borgatti, S.P., Mehra, A., Brass, D. and Labianca, G. (2009). "Network Analysis in the Social Sciences." Science. Vol. 323. no. 5916, 892 - 895.
- Chris Caldwell: Graph theory Glossary at
  http://www.utm.edu/departments/math/graph/glossary.html
- Hanneman, R. Introduction to Social Networks. Online book free on the web at http://faculty.ucr.edu/~hanneman/nettext/
- Marsden, P.V. (1990) Network data and measurement. Annual Review of Sociology 16:435-63.
- Marsden, P.V. (2005) Recent developments in network measurement. Chapter 2 (pp. 8-30) in P.J. Carrington, J. Scott, and S. Wasserman (eds.), Models and methods in social network analysis, (2005). Cambridge University Press.
- Moody, J. and Paxton, P. (2009), Building Bridges : Linking Social Capital and Social Networks to Improve theory and research . American Behavioral Scientist, 52, 1491-1506.
- Butts C.T. (2008). Social Network Analysis with sna. Journal of Statistical Software, 24(6), http://www.jstatsoft.org/v24/i06/
- Network Analysis with igraph, http://igraph.sourceforge.net/igraphbook/
- Newman, M.E.J. (2010) Networks: An Introduction , Oxford University Press, Oxford. This is introduced as an alternative general reference which covers many of the topics discussed, although not only from the perspective of social network analysis.
- Travers, J. and Milgram, S. (1969) An experimental study of the small world problem. Sociometry 32:425-443.
- Dodds, P. S., Muhamad, R., and Watts, D.J. (2003) An experimental study of search in global social networks. Science 301:827-829.
- Watts, D.J. and Strogatz, S.H. (1998) Collective dynamics of "small-world" networks. Nature 393: 440-442.
  For an implementation of the Watts-Strogatz model in R, look at watts.strogatz.game in igraph.
- Kleinberg, J.M. (2000) Navigation in a small world. Science 406:845.
- Watts, D.J. (2004) The "new" science of networks. Annual Review of Sociology 30:243-270.
- Fleming, L., King III, C. and Watts, D.J. (2007) Small worlds and regional innovation. Organization Science 18:938-954.
- Centola, D. (2010) The spread of behaviour in an online social networking experiment. Science 329:1194-1197.
- Clauset, A., Shalizi, C.R., and Newman, M.E.J. (2009) Power-law distributions in empirical data. SIAM Review 51:661-703.
  To implement the analysis described in this paper, you can obtain the code in R from http://tuvalu.santafe.edu/~aaronc/powerlaws/.
- Barabási, A.-L. and Albert, R. (1999) Emergence of scaling in random networks. Science 286: 509-512.
  For an implementation of the Barabasi-Albert model in R, look at barabasi.game in igraph.
- Merton, R. (1968) The Matthew effect in science. Science 159:56-63.
- Amaral, L.A.N., Scala, A., Barthelemy, M. and Stanley, H.E. (2000) Classes of small world networks. Proceedings of the National Academy of Sciences 97:11149-11152.
- Powell, W.W., White, D.R., Koput, K.W. and Owen-Smith J (2005) Network dynamics and field evolution: The growth of interorganizational collaboration in the life sciences. American Journal of Sociology 69:213-238.
- Saavedra, S., Reed-Tsochas, F. and Uzzi, B. (2008) Asymmetric disassembly and robustness in declining networks. Proceedings of the National Academy of Sciences 105:16466-16471.
- Moody, J. (2004). The structure of a social science collaboration network: Disciplinary cohesion from 1963-1999. American Sociological Review 69:213-238.
- Guimerà, R., Uzzi, B., Spiro, J., and Amaral, L.A.N. (2005) Team assembly mechanisms determine collaboration network structure and team performance. Science 308:697-702.
- Uzzi, B. and Spiro, J. (2005) Collaboration and creativity: The small world problem. American Journal of Sociology 111:447-504.
- Robins, G.L., Woolcock, J., and Pattison, P. (2005) Small and other worlds: Global network structures from local processes.
  American Journal of Sociology , 110, 894-936.
- Snijders, T.A.B., Steglich, C.E.G., and van de Bunt, G.G., (2010). Introduction to actor-based models for network dynamics. Social Networks, 32, 44-60.
- Maarten Van Zalk / Selfhout, William Burk, Susan Branje, Jaap Denissen, Marcel van Aken, and Wim Meeus (2010). Emerging late adolescent friendship networks and big five personality traits: A social network approach. Journal of Personality, 78, 509-538.
- Noona Kiuru, William J. Burk, Brett Laursen, Katariina Salmela-Aro, and Jari-Erik Nurmi (2010). Pressure to drink but not to smoke: Disentangling selection and socialization in adolescent peer networks and peer groups. Journal of Adolescence, 33, 801-812.
- Ripley, R., and Snijders, T.A.B. (2011) Manual for SIENA version 4.0. University of Oxford: Department of Statistics and Nuffield College.

R materials

Some websites and resources that can be very helpful for the beginning R user:

Some Hints for the R Beginner by Patrick Burns with the memorable quote "I asked R users what their biggest stumbling blocks were in learning R. A common answer that I was quite surprised by was that the biggest stumbling block was thinking that R was hard".
Excellent simple intro to R from Princeton.
Getting started with R by J. Gardner.
The official R intro
A portal with pointers to other R resources .
R Starter kit from UCLA.
Quick R website (intended especially for experienced users of other statistical software).