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Social network analysis

A social network diagram displaying friendship ties among a set of Facebook users.

Social network analysis (SNA) is the process of investigating social structures through the use of network and graph theories.[1] It characterizes networked structures in terms of nodes (individual actors, people, or things within the network) and the ties or edges (relationships or interactions) that connect them. Examples of social structures commonly visualized through social network analysis include social media networks, friendship and acquaintance networks, kinship, disease transmission,and sexual relationships.[2][3] These networks are often visualized through sociograms in which nodes are represented as points and ties are represented as lines.

Social network analysis has emerged as a key technique in modern political science, social psychology, development studies, and sociolinguistics and is now commonly available as a consumer tool.[4][5][6][7]


  • History 1
  • Metrics 2
    • Connections 2.1
    • Distributions 2.2
    • Segmentation 2.3
  • Modelling and visualization of networks 3
  • Practical applications 4
  • See also 5
  • References 6
  • External links 7
    • Further reading 7.1
    • Organizations 7.2
    • Peer-reviewed journals 7.3
    • Textbooks and educational resources 7.4
    • Data sets 7.5


Social network analysis has its theoretical roots in the work of early sociologists such as Émile Durkheim, who wrote about the importance of studying patterns of relationships that connect social actors. Social scientists have used the concept of "social networks" since early in the 20th century to connote complex sets of relationships between members of social systems at all scales, from interpersonal to international. In the 1930s Jacob Moreno and Helen Jennings introduced basic analytical methods.[8] In 1954, John Arundel Barnes started using the term systematically to denote patterns of ties, encompassing concepts traditionally used by the public and those used by social scientists: bounded groups (e.g., tribes, families) and social categories (e.g., gender, ethnicity). Scholars such as Ronald Burt, Kathleen Carley, Mark Granovetter, David Krackhardt, Edward Laumann, Anatol Rapoport, Barry Wellman, Douglas R. White, and Harrison White expanded the use of systematic social network analysis.[9] Even in the study of literature, network analysis has been applied by Anheier, Gerhards and Romo,[10] Wouter De Nooy,[11] and Burgert Senekal.[12] Indeed, social network analysis has found applications in various academic disciplines, as well as practical applications such as countering money laundering and terrorism.


Hue (from red=0 to blue=max) indicates each node's betweenness centrality.


Homophily: The extent to which actors form ties with similar versus dissimilar others. Similarity can be defined by gender, race, age, occupation, educational achievement, status, values or any other salient characteristic.[13] Homophily is also referred to as assortativity.

Multiplexity: The number of content-forms contained in a tie.[14] For example, two people who are friends and also work together would have a multiplexity of 2.[15] Multiplexity has been associated with relationship strength.

Mutuality/Reciprocity: The extent to which two actors reciprocate each other’s friendship or other interaction.[16]

Network Closure: A measure of the completeness of relational triads. An individual’s assumption of network closure (i.e. that their friends are also friends) is called transitivity. Transitivity is an outcome of the individual or situational trait of Need for Cognitive Closure.[17]

Propinquity: The tendency for actors to have more ties with geographically close others.[16]


Bridge: An individual whose weak ties fill a structural hole, providing the only link between two individuals or clusters. It also includes the shortest route when a longer one is unfeasible due to a high risk of message distortion or delivery failure.[18]

Centrality: Centrality refers to a group of metrics that aim to quantify the "importance" or "influence" (in a variety of senses) of a particular node (or group) within a network.[19][20][21][22] Examples of common methods of measuring "centrality" include betweenness centrality,[23] closeness centrality, eigenvector centrality, alpha centrality and degree centrality.[24]

Density: The proportion of direct ties in a network relative to the total number possible.[25][26]

Distance: The minimum number of ties required to connect two particular actors, as popularized by Stanley Milgram’s small world experiment and the idea of ‘six degrees of separation’.

Structural holes: The absence of ties between two parts of a network. Finding and exploiting a structural hole can give an entrepreneur a competitive advantage. This concept was developed by sociologist Ronald Burt, and is sometimes referred to as an alternate conception of social capital.

Tie Strength: Defined by the linear combination of time, emotional intensity, intimacy and reciprocity (i.e. mutuality).[18] Strong ties are associated with homophily, propinquity and transitivity, while weak ties are associated with bridges.


Groups are identified as ‘cliques’ if every individual is directly tied to every other individual, ‘social circles’ if there is less stringency of direct contact, which is imprecise, or as structurally cohesive blocks if precision is wanted.[27]

Clustering coefficient: A measure of the likelihood that two associates of a node are associates. A higher clustering coefficient indicates a greater 'cliquishness'.[28]

Cohesion: The degree to which actors are connected directly to each other by cohesive bonds. Structural cohesion refers to the minimum number of members who, if removed from a group, would disconnect the group.[29][30]

Modelling and visualization of networks

Visual representation of social networks is important to understand the network data and convey the result of the analysis [3]. Numerous methods of visualization for data produced by Social Network Analysis have been presented.[31][32][33] Many of the analytic software have modules for network visualization. Exploration of the data is done through displaying nodes and ties in various layouts, and attributing colors, size and other advanced properties to nodes. Visual representations of networks may be a powerful method for conveying complex information, but care should be taken in interpreting node and graph properties from visual displays alone, as they may misrepresent structural properties better captured through quantitative analyses.[34]

Collaboration graphs can be used to illustrate good and bad relationships between humans. A positive edge between two nodes denotes a positive relationship (friendship, alliance, dating) and a negative edge between two nodes denotes a negative relationship (hatred, anger). Signed social network graphs can be used to predict the future evolution of the graph. In signed social networks, there is the concept of "balanced" and "unbalanced" cycles. A balanced cycle is defined as a cycle where the product of all the signs are positive. Balanced graphs represent a group of people who are unlikely to change their opinions of the other people in the group. Unbalanced graphs represent a group of people who are very likely to change their opinions of the people in their group. For example, a group of 3 people (A, B, and C) where A and B have a positive relationship, B and C have a positive relationship, but C and A have a negative relationship is an unbalanced cycle. This group is very likely to morph into a balanced cycle, such as one where B only has a good relationship with A, and both A and B have a negative relationship with C. By using the concept of balanced and unbalanced cycles, the evolution of signed social network graphs can be predicted.

Especially when using social network analysis as a tool for facilitating change, different approaches of participatory network mapping have proven useful. Here participants / interviewers provide network data by actually mapping out the network (with pen and paper or digitally) during the data collection session. An example of a pen-and-paper network mapping approach, which also includes the collection of some actor attributes (perceived influence and goals of actors) is the * Net-map toolbox. One benefit of this approach is that it allows researchers to collect qualitative data and ask clarifying questions while the network data is collected.[35]

Practical applications

Social network analysis is used extensively in a wide range of applications and disciplines. Some common network analysis applications include data aggregation and mining, network propagation modeling, network modeling and sampling, user attribute and behavior analysis, community-maintained resource support, location-based interaction analysis, social sharing and filtering, recommender systems development, and link prediction and entity resolution.[36] In the private sector, businesses use social network analysis to support activities such as customer interaction and analysis, information system development analysis,[37] marketing, and business intelligence needs. Some public sector uses include development of leader engagement strategies, analysis of individual and group engagement and media use, and community-based problem solving.

Social network analysis is also used in intelligence, National Security Agency (NSA) uses its clandestine mass electronic surveillance programs to generate the data needed to perform this type of analysis on terrorist cells and other networks deemed relevant to national security. The NSA looks up to three nodes deep during this network analysis.[38] After the initial mapping of the social network is complete, analysis is performed to determine the structure of the network and determine, for example, the leaders within the network.[39] This allows military or law enforcement assets to launch capture-or-kill decapitation attacks on the high-value targets in leadership positions to disrupt the functioning of the network.

The NSA has been performing social network analysis on Call Detail Records (CDRs), also known as metadata, since shortly after the September 11 Attacks.[40][41]

Large textual corpora can be turned into networks and then analysed with the method of Social Network Analysis. In these networks, the nodes are Social Actors, and the links are Actions. The extraction of these networks can be automated, by using parsers.

Narrative network of US Elections 2012[42]

The resulting networks, which can contain thousands of nodes, are then analysed by using tools from Network theory to identify the key actors, the key communities or parties, and general properties such as robustness or structural stability of the overall network, or centrality of certain nodes.[43] This automates the approach introduced by Quantitative Narrative Analysis,[44] whereby subject-verb-object triplets are identified with pairs of actors linked by an action, or pairs formed by actor-object.[42]

See also


  1. ^ Otte, Evelien; Rousseau, Ronald (2002). "Social network analysis: a powerful strategy, also for the information sciences". Journal of Information Science 28: 441–453.  
  2. ^ Pinheiro, Carlos A.R. (2011). Social Network Analysis in Telecommunications. John Wiley & Sons. p. 4.  
  3. ^ D'Andrea, Alessia et al. (2009). "An Overview of Methods for Virtual Social Network Analysis". In Abraham, Ajith et al. Computational Social Network Analysis: Trends, Tools and Research Advances. Springer. p. 8.  
  4. ^ Facebook friends mapped by Wolfram Alpha app BBC News
  5. ^ Wolfram Alpha Launches Personal Analytics Reports For Facebook Tech Crunch
  6. ^ [4]
  7. ^ Ivaldi M., Ferreri L., Daolio F., Giacobini M., Tomassini M., Rainoldi A., We-Sport: from academy spin-off to data-base for complex network analysis; an innovative approach to a new technology. J Sports Med and Phys Fitnes Vol. 51-suppl. 1 to issue No. 3. The social network analysis was used to analyze properties of the network allowing a deep interpretation and analysis of the level of aggregation phenomena in the specific context of sport and physical exercise.
  8. ^ Freeman, L. C. (2004). The development of social network analysis: a study in the sociology of science. Vancouver, B. C.: Empirical Press. 
  9. ^ Linton Freeman, The Development of Social Network Analysis. Vancouver: Empirical Press, 2006.
  10. ^ Anheier, H.K.; Gerhards, J.; Romo, F.P. (1995). "Forms of capital and social structure of fields: examining Bourdieu's social topography". American Journal of Sociology 100: 859–903.  
  11. ^ De Nooy, W (2003). "Fields and networks: Correspondence analysis and social network analysis in the framework of Field Theory". Poetics 31: 305–27.  
  12. ^ Senekal, B. A. 2012. Die Afrikaanse literêre sisteem: ʼn Eksperimentele benadering met behulp van Sosiale-netwerk-analise (SNA), LitNet Akademies 9(3)
  13. ^ McPherson, N., Smith-Lovin, L., Cook, J.M. (2001). Birds of a feather: Homophily in social networks. Annual Review of Sociology 27. pp. 415–444.  
  14. ^ Podolny, J.M. & Baron, J.N. (1997). Resources and relationships: Social networks and mobility in the workplace. American Sociological Review, 62(5), 673-693.
  15. ^ Kilduff, M., Tsai, W. (2003). Social networks and organisations. Sage Publications. 
  16. ^ a b Kadushin, C. (2012). Understanding social networks: Theories, concepts, and findings. Oxford: Oxford University Press
  17. ^ Flynn, F.J.; Reagans, R.E.; Guillory, L. (2010). "Do you two know each other? Transitivity, homophily, and the need for (network) closure". Journal of Personality and Social Psychology 99 (5): 855–869.  
  18. ^ a b Granovetter, M. (1973). The strength of weak ties. American Journal of Sociology 78 (6). pp. 1360–1380.  
  19. ^ Hansen, Derek et al. (2010). Analyzing Social Media Networks with NodeXL. Morgan Kaufmann. p. 32.  
  20. ^ Liu, Bing (2011). Web Data Mining: Exploring Hyperlinks, Contents, and Usage Data. Springer. p. 271.  
  21. ^ Hanneman, Robert A. & Riddle, Mark (2011). "Concepts and Measures for Basic Network Analysis". The Sage Handbook of Social Network Analysis. SAGE. pp. 364–367.  
  22. ^ Tsvetovat, Maksim & Kouznetsov, Alexander (2011). Social Network Analysis for Startups: Finding Connections on the Social Web. O'Reilly. p. 45.  
  23. ^ The most comprehensive reference is: Wasserman, Stanley, & Faust, Katherine. (1994). Social Networks Analysis: Methods and Applications. Cambridge: Cambridge University Press. A short, clear basic summary is in Krebs, Valdis. (2000). "The Social Life of Routers." Internet Protocol Journal, 3 (December): 14–25.
  24. ^ Opsahl, Tore; Agneessens, Filip; Skvoretz, John (2010). "Node centrality in weighted networks: Generalizing degree and shortest paths". Social Networks 32 (3): 245–251.  
  25. ^ "Social Network Analysis". Field Manual 3-24: Counterinsurgency (PDF). Headquarters,  
  26. ^ Xu, Guandong et al. (2010). Web Mining and Social Networking: Techniques and Applications. Springer. p. 25.  
  27. ^ Cohesive.blocking is the R program for computing structural cohesion according to the Moody-White (2003) algorithm. This wiki site provides numerous examples and a tutorial for use with R.
  28. ^ Hanneman, Robert A. & Riddle, Mark (2011). "Concepts and Measures for Basic Network Analysis". The Sage Handbook of Social Network Analysis. SAGE. pp. 346–347.  
  29. ^ Moody, James, and Douglas R. White (2003). "Structural Cohesion and Embeddedness: A Hierarchical Concept of Social Groups." American Sociological Review 68(1):103–127. Online: (PDF file).
  30. ^ Pattillo, Jeffrey et al. (2011). "Clique relaxation models in social network analysis". In Thai, My T. & Pardalos, Panos M. Handbook of Optimization in Complex Networks: Communication and Social Networks. Springer. p. 149.  
  31. ^ Hamdaqa, Mohammad; Tahvildari, Ladan; LaChapelle, Neil; Campbell, Brian (2014). "Cultural Scene Detection Using Reverse Louvain Optimization". Science of Computer Programming 95: 44–72.  
  32. ^ Bacher, R. (1995). Graphical Interaction and Visualization for the Analysis and Interpretation of Contingency Analysis Result. In Proceedings of the 1995 Power Industry Computer Applications (pp . 128-134) . Salt Lake City, USA: IEEE Power Engineering Society
  33. ^ Caschera, M. C.; Ferri, F.; Grifoni, P. (2008). "SIM: A dynamic multidimensional visualization method for social networks". PsychNology Journal 6 (3): 291–320. 
  34. ^ McGrath, Blythe and Krackhardt. 1997. "The effect of spatial arrangement on judgements and errors in interpreting graphs". Social Networks 19: 223-242.
  35. ^ Bernie Hogan, Juan-Antonio Carrasco and Barry Wellman, "Visualizing Personal Networks: Working with Participant-Aided Sociograms," Field Methods 19 (2), May 2007: 116-144.
  36. ^ Golbeck, J. (2013). Analyzing the Social Web. Morgan Kaufmann, ISBN 0-12-405856-6>
  37. ^ Aram, Michael; Neumann, Gustaf (2015-07-01). "Multilayered analysis of co-development of business information systems" (PDF). Journal of Internet Services and Applications 6 (1).  
  38. ^ "NSA warned to rein in surveillance as agency reveals even greater scope". 17 July 2013. Retrieved 19 July 2013. 
  39. ^ "How The NSA Uses Social Network Analysis To Map Terrorist Networks". 12 June 2013. Retrieved 19 Jul 2013. 
  40. ^ "NSA Using Social Network Analysis". 12 May 2006. Retrieved 19 July 2013. 
  41. ^ "NSA has massive database of Americans' phone calls". 11 May 2006. Retrieved 19 July 2013. 
  42. ^ a b Automated analysis of the US presidential elections using Big Data and network analysis; S Sudhahar, GA Veltri, N Cristianini; Big Data & Society 2 (1), 1-28, 2015
  43. ^ Network analysis of narrative content in large corpora; S Sudhahar, G De Fazio, R Franzosi, N Cristianini; Natural Language Engineering, 1-32, 2013
  44. ^ Quantitative Narrative Analysis; Roberto Franzosi; Emory University © 2010

External links

Further reading

  • Introduction to Stochastic Actor-Based Models for Network Dynamics - Snijders et al.
  • The International Network for Social Network Analysis (INSNA) – professional society of social network analysts, with more than 1,000 members
  • Center for Computational Analysis of Social and Organizational Systems (CASOS) at Carnegie Mellon
  • NetLab at the University of Toronto, studies the intersection of social, communication, information and computing networks
  • Netwiki (wiki page devoted to social networks; maintained at University of North Carolina at Chapel Hill)
  • Program on Networked Governance – Program on Networked Governance, Harvard University
  • The International Workshop on Social Network Analysis and Mining (SNA-KDD) - An annual workshop on social network analysis and mining, with participants from computer science, social science, and related disciplines.
  • Historical Dynamics in a time of Crisis: Late Byzantium, 1204–1453 (a discussion of social network analysis from the point of view of historical studies)
  • Social Network Analysis: A Systematic Approach for Investigating


  • International Network for Social Network Analysis

Peer-reviewed journals

  • Social Networks
  • Network Science
  • Journal of Social Structure
  • Journal of Complex Networks
  • Journal of Mathematical Sociology
  • Social Network Analysis and Mining (SNAM)
  • "Connections". Toronto: International Network for Social Network Analysis.  

Textbooks and educational resources

  • Networks, Crowds, and Markets (2010) by D. Easley & J. Kleinberg
  • Introduction to Social Networks Methods (2005) by R. Hanneman & M. Riddle
  • Analyzing the Social Web (2013) by J. Golbeck

Data sets

  • Pajek's list of lists of datasets
  • UC Irvine Network Data Repository
  • Stanford Large Network Dataset Collection
  • M.E.J. Newman datasets
  • Pajek datasets
  • Gephi datasets
  • KONECT - Koblenz network collection
  • RSiena datasets
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