Social network

Social network

Overview
A social network is a social structure
Social structure
Social structure is a term used in the social sciences to refer to patterned social arrangements in society that are both emergent from and determinant of the actions of the individuals. The usage of the term "social structure" has changed over time and may reflect the various levels of analysis...

 made up of individuals (or organizations) called "nodes", which are tied (connected) by one or more specific types of interdependency, such as friendship
Friendship
Friendship is a form of interpersonal relationship generally considered to be closer than association, although there is a range of degrees of intimacy in both friendships and associations. Friendship and association are often thought of as spanning across the same continuum...

, kinship
Kinship
Kinship is a relationship between any entities that share a genealogical origin, through either biological, cultural, or historical descent. And descent groups, lineages, etc. are treated in their own subsections....

, common interest, financial exchange, dislike, sexual relationships
Sexual network
A sexual network is a social network that is defined by the sexual relationships within a set of individuals.-Studies and discoveries:Like other forms of social networks, sexual networks can be formally studied using the mathematics of graph theory and network theory.Recent epidemiological studies ...

, or relationships of beliefs, knowledge or prestige.

Social network analysis (SNA) views social relationships in terms of network theory
Network theory
Network theory is an area of computer science and network science and part of graph theory. It has application in many disciplines including statistical physics, particle physics, computer science, biology, economics, operations research, and sociology...

 consisting of nodes and ties (also called edges, links, or connections).
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Encyclopedia
A social network is a social structure
Social structure
Social structure is a term used in the social sciences to refer to patterned social arrangements in society that are both emergent from and determinant of the actions of the individuals. The usage of the term "social structure" has changed over time and may reflect the various levels of analysis...

 made up of individuals (or organizations) called "nodes", which are tied (connected) by one or more specific types of interdependency, such as friendship
Friendship
Friendship is a form of interpersonal relationship generally considered to be closer than association, although there is a range of degrees of intimacy in both friendships and associations. Friendship and association are often thought of as spanning across the same continuum...

, kinship
Kinship
Kinship is a relationship between any entities that share a genealogical origin, through either biological, cultural, or historical descent. And descent groups, lineages, etc. are treated in their own subsections....

, common interest, financial exchange, dislike, sexual relationships
Sexual network
A sexual network is a social network that is defined by the sexual relationships within a set of individuals.-Studies and discoveries:Like other forms of social networks, sexual networks can be formally studied using the mathematics of graph theory and network theory.Recent epidemiological studies ...

, or relationships of beliefs, knowledge or prestige.

Social network analysis (SNA) views social relationships in terms of network theory
Network theory
Network theory is an area of computer science and network science and part of graph theory. It has application in many disciplines including statistical physics, particle physics, computer science, biology, economics, operations research, and sociology...

 consisting of nodes and ties (also called edges, links, or connections). Nodes
Node (computer science)
A node is a record consisting of one or more fields that are links to other nodes, and a data field. The link and data fields are often implemented by pointers or references although it is also quite common for the data to be embedded directly in the node. Nodes are used to build linked, often...

 are the individual actors within the networks, and ties are the relationships between the actors. The resulting graph
Graph (mathematics)
In mathematics, a graph is an abstract representation of a set of objects where some pairs of the objects are connected by links. The interconnected objects are represented by mathematical abstractions called vertices, and the links that connect some pairs of vertices are called edges...

-based structures are often very complex
Complex network
In the context of network theory, a complex network is a graph with non-trivial topological features—features that do not occur in simple networks such as lattices or random graphs but often occur in real graphs...

. There can be many kinds of ties between the nodes. Research in a number of academic fields has shown that social networks operate on many levels, from families up to the level of nations, and play a critical role in determining the way problems are solved, organizations are run, and the degree to which individuals succeed in achieving their goals.

In its simplest form, a social network is a map of specified ties, such as friendship, between the nodes being studied. The nodes to which an individual is thus connected are the social contacts of that individual. The network can also be used to measure social capital
Social capital
Social capital is a sociological concept, which refers to connections within and between social networks. The concept of social capital highlights the value of social relations and the role of cooperation and confidence to get collective or economic results. The term social capital is frequently...

 – the value that an individual gets from the social network. These concepts are often displayed in a social network diagram
Network diagram
A computer network diagram is a schematic depicting the nodes and connections amongst nodes in a computer network or, more generally, any telecommunications network.-Symbolization:...

, where nodes are the points and ties are the lines.

Social network analysis



Social network analysis (related to network theory
Network theory
Network theory is an area of computer science and network science and part of graph theory. It has application in many disciplines including statistical physics, particle physics, computer science, biology, economics, operations research, and sociology...

) has emerged as a key technique in modern sociology
Sociology
Sociology is the study of society. It is a social science—a term with which it is sometimes synonymous—which uses various methods of empirical investigation and critical analysis to develop a body of knowledge about human social activity...

. It has also gained a significant following in anthropology
Anthropology
Anthropology is the study of humanity. It has origins in the humanities, the natural sciences, and the social sciences. The term "anthropology" is from the Greek anthrōpos , "man", understood to mean mankind or humanity, and -logia , "discourse" or "study", and was first used in 1501 by German...

, biology
Biology
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy. Biology is a vast subject containing many subdivisions, topics, and disciplines...

, communication studies
Communication studies
Communication Studies is an academic field that deals with processes of communication, commonly defined as the sharing of symbols over distances in space and time. Hence, communication studies encompasses a wide range of topics and contexts ranging from face-to-face conversation to speeches to mass...

, economics
Economics
Economics is the social science that analyzes the production, distribution, and consumption of goods and services. The term economics comes from the Ancient Greek from + , hence "rules of the house"...

, geography
Geography
Geography is the science that studies the lands, features, inhabitants, and phenomena of Earth. A literal translation would be "to describe or write about the Earth". The first person to use the word "geography" was Eratosthenes...

, information science
Information science
-Introduction:Information science is an interdisciplinary science primarily concerned with the analysis, collection, classification, manipulation, storage, retrieval and dissemination of information...

, organizational studies
Organizational studies
Organizational studies, sometimes known as organizational science, encompass the systematic study and careful application of knowledge about how people act within organizations...

, social psychology
Social psychology
Social psychology is the scientific study of how people's thoughts, feelings, and behaviors are influenced by the actual, imagined, or implied presence of others. By this definition, scientific refers to the empirical method of investigation. The terms thoughts, feelings, and behaviors include all...

, and sociolinguistics
Sociolinguistics
Sociolinguistics is the descriptive study of the effect of any and all aspects of society, including cultural norms, expectations, and context, on the way language is used, and the effects of language use on society...

, and has become a popular topic of speculation and study.

People have used the idea of "social network" loosely for over a century to connote complex sets of relationships between members of social systems at all scales, from interpersonal to international. In 1954, J. A. 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
Group (sociology)
In the social sciences a social group can be defined as two or more humans who interact with one another, share similar characteristics and collectively have a sense of unity...

 (e.g., tribes, families) and social categories
Categorization
Categorization is the process in which ideas and objects are recognized, differentiated and understood. Categorization implies that objects are grouped into categories, usually for some specific purpose. Ideally, a category illuminates a relationship between the subjects and objects of knowledge...

 (e.g., gender, ethnicity). Scholars such as S.D. Berkowitz, Stephen Borgatti, Ronald Burt, Kathleen Carley
Kathleen Carley
Kathleen M. Carley is an American social scientist specializing in dynamic network analysis. She is a professor in the School of Computer Science in the Institute for Software Research International at Carnegie Mellon University and also holds appointments in the Tepper School of Business, the...

, Martin Everett, Katherine Faust, Linton Freeman, Mark Granovetter
Mark Granovetter
Professor Mark Granovetter is an American sociologist at Stanford University who has created theories in modern sociology since the 1970s. He is best known for his work in social network theory and in economic sociology, particularly his theory on the spread of information in social networks known...

, David Knoke, David Krackhardt
David Krackhardt
David Krackhardt is Professor of Organizations at the Heinz College, the Tepper School of Business, and the Department of Social and Decision Sciences at Carnegie Mellon University in the United States...

, Peter Marsden, Nicholas Mullins, Anatol Rapoport, Stanley Wasserman, Barry Wellman
Barry Wellman
Barry Wellman, FRSC directs NetLab as the S.D. Clark Professor of Sociology at the University of Toronto. His areas of research are community sociology, the Internet, human-computer interaction and social structure, as manifested in social networks in communities and organizations...

, Douglas R. White
Douglas R. White
Douglas R. White is an American complexity researcher , social anthropologist, sociologist, and social network researcher at the University of California, Irvine.-Biography:...

, and Harrison White
Harrison White
Harrison Colyar White is the emeritus Giddings Professor of Sociology at Columbia University. White is an influential scholar in the domain of social networks. He is credited with the development of a number of mathematical models of social structure including vacancy chains and blockmodels...

 expanded the use of systematic social network analysis.

Social network analysis has now moved from being a suggestive metaphor to an analytic approach to a paradigm, with its own theoretical statements, methods, social network analysis software
Social network analysis software
Social network analysis software facilitates quantitative or qualitative analysis of social networks, by describing features of a network, either through numerical or visual representation...

, and researchers. Analysts reason from whole to part; from structure to relation to individual; from behavior to attitude. They typically either study whole networks (also known as complete networks), all of the ties containing specified relations in a defined population, or personal networks (also known as egocentric networks), the ties that specified people have, such as their "personal communities". In the latter case, the ties are said to go from egos, who are the focal actors who are being analyzed, to their alters. The distinction between whole/complete networks and personal/egocentric networks has depended largely on how analysts were able to gather data. That is, for groups such as companies, schools, or membership societies, the analyst was expected to have complete information about who was in the network, all participants being both potential egos and alters. Personal/egocentric studies were typically conducted when identities of egos were known, but not their alters. These studies rely on the egos to provide information about the identities of alters and there is no expectation that the various egos or sets of alters will be tied to each other. A snowball network refers to the idea that the alters identified in an egocentric survey then become egos themselves and are able in turn to nominate additional alters. While there are severe logistic limits to conducting snowball network studies, a method for examining hybrid networks has recently been developed in which egos in complete networks can nominate alters otherwise not listed who are then available for all subsequent egos to see. The hybrid network may be valuable for examining whole/complete networks that are expected to include important players beyond those who are formally identified. For example, employees of a company often work with non-company consultants who may be part of a network that cannot fully be defined prior to data collection.

Several analytic tendencies distinguish social network analysis:
There is no assumption that groups are the building blocks of society: the approach is open to studying less-bounded social systems, from nonlocal communities to links among website
Website
A website, also written as Web site, web site, or simply site, is a collection of related web pages containing images, videos or other digital assets. A website is hosted on at least one web server, accessible via a network such as the Internet or a private local area network through an Internet...

s.

Rather than treating individuals (persons, organizations, states) as discrete units of analysis, it focuses on how the structure of ties affects individuals and their relationships.

In contrast to analyses that assume that socialization into norms determines behavior, network analysis looks to see the extent to which the structure and composition of ties affect norms.


The shape of a social network helps determine a network's usefulness to its individuals. Smaller, tighter networks can be less useful to their members than networks with lots of loose connections (weak ties) to individuals outside the main network. More open networks, with many weak ties and social connections, are more likely to introduce new ideas and opportunities to their members than closed networks with many redundant ties. In other words, a group of friends who only do things with each other already share the same knowledge and opportunities. A group of individuals with connections to other social worlds is likely to have access to a wider range of information. It is better for individual success to have connections to a variety of networks rather than many connections within a single network. Similarly, individuals can exercise influence or act as brokers within their social networks by bridging two networks that are not directly linked (called filling structural holes).

The power of social network analysis stems from its difference from traditional social scientific studies, which assume that it is the attributes of individual actors—whether they are friendly or unfriendly, smart or dumb, etc.—that matter. Social network analysis produces an alternate view, where the attributes of individuals are less important than their relationships and ties with other actors within the network. This approach has turned out to be useful for explaining many real-world phenomena, but leaves less room for individual agency, the ability for individuals to influence their success, because so much of it rests within the structure of their network.

Social networks have also been used to examine how organizations interact with each other, characterizing the many informal connections that link executives together, as well as associations and connections between individual employees at different organizations. For example, power within organizations often comes more from the degree to which an individual within a network is at the center of many relationships than actual job title. Social networks also play a key role in hiring, in business success, and in job performance. Networks provide ways for companies to gather information, deter competition, and collude
Collusion
Collusion is an agreement between two or more persons, sometimes illegal and therefore secretive, to limit open competition by deceiving, misleading, or defrauding others of their legal rights, or to obtain an objective forbidden by law typically by defrauding or gaining an unfair advantage...

 in setting prices or policies.

History of social network analysis


A summary of the progress of social networks and social network analysis has been written by Linton Freeman.

Precursors of social networks in the late 1800s include Émile Durkheim
Émile Durkheim
David Émile Durkheim was a French sociologist. He formally established the academic discipline and, with Karl Marx and Max Weber, is commonly cited as the principal architect of modern social science and father of sociology.Much of Durkheim's work was concerned with how societies could maintain...

 and Ferdinand Tönnies
Ferdinand Tönnies
Ferdinand Tönnies was a German sociologist. He was a major contributor to sociological theory and field studies, best known for his distinction between two types of social groups, Gemeinschaft and Gesellschaft...

. Tönnies argued that social groups can exist as personal and direct social ties that either link individuals who share values and belief (gemeinschaft) or impersonal, formal, and instrumental social links (gesellschaft). Durkheim gave a non-individualistic explanation of social facts arguing that social phenomena arise when interacting individuals constitute a reality that can no longer be accounted for in terms of the properties of individual actors. He distinguished between a traditional society – "mechanical solidarity" – which prevails if individual differences are minimized, and the modern society – "organic solidarity" – that develops out of cooperation between differentiated individuals with independent roles.

Georg Simmel
Georg Simmel
Georg Simmel was a major German sociologist, philosopher, and critic.Simmel was one of the first generation of German sociologists: his neo-Kantian approach laid the foundations for sociological antipositivism, asking 'What is society?' in a direct allusion to Kant's question 'What is nature?',...

, writing at the turn of the twentieth century, was the first scholar to think directly in social network terms. His essays pointed to the nature of network size on interaction and to the likelihood of interaction in ramified, loosely-knit networks rather than groups (Simmel, 1908/1971).

After a hiatus in the first decades of the twentieth century, three main traditions in social networks appeared. In the 1930s, J.L. Moreno
Jacob L. Moreno
Jacob Levy Moreno was a Jewish Romanian-born Austrian-American leading psychiatrist and psychosociologist, thinker and educator, the founder of psychodrama, and the foremost pioneer of group psychotherapy...

 pioneered the systematic recording and analysis of social interaction in small groups, especially classrooms and work groups (sociometry
Sociometry
Sociometry is a quantitative method for measuring social relationships. It was developed by psychotherapist Jacob L. Moreno in his studies of the relationship between social structures and psychological well-being....

), while a Harvard group led by W. Lloyd Warner
W. Lloyd Warner
William Lloyd Warner was a pioneering anthropologist noted for applying the techniques of his discipline to contemporary American culture.-Career at Harvard:...

 and Elton Mayo
Elton Mayo
George Elton Mayo was an Australian psychologist, sociologist and organization theorist.He lectured at the University of Queensland from 1911 to 1923 before moving to the University of Pennsylvania, but spent most of his career at Harvard Business School , where he was professor of industrial...

 explored interpersonal relations at work. In 1940, A.R. Radcliffe-Brown's presidential address to British anthropologists urged the systematic study of networks. However, it took about 15 years before this call was followed-up systematically.

Social network analysis developed with the kinship studies of Elizabeth Bott in England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...

 in the 1950s and the 1950s–1960s urbanization
Urbanization
Urbanization, urbanisation or urban drift is the physical growth of urban areas as a result of global change. The United Nations projected that half of the world's population would live in urban areas at the end of 2008....

 studies of the University of Manchester group
Manchester school (anthropology)
The Department of Social Anthropology at the University of Manchester, founded by Max Gluckman in 1947 became known among anthropologists and other social scientists as the Manchester School. Notable features of the Manchester School included an emphasis on "case studies", deriving from Gluckman's...

 of anthropologists (centered around Max Gluckman
Max Gluckman
Max Gluckman was a South African and British social anthropologist.He grew up in South Africa, working later under the British Administration in Northern Rhodesia...

 and later J. Clyde Mitchell
J. Clyde Mitchell
James Clyde Mitchell was a British sociologist and anthropologist....

) investigating community networks in southern Africa, India and the United Kingdom. Concomitantly, British anthropologist S.F. Nadel
Siegfried Frederick Nadel
Siegfried Frederick Nadel , known as Fred Nadel, was an Austrian-born British anthropologist, specialising in African ethnology.-Biography:Nadel was born in Lemberg, Galizia, the son of a lawyer...

 codified a theory of social structure that was influential in later network analysis.

In the 1960s-1970s, a growing number of scholars worked to combine the different tracks and traditions. One group was centered around Harrison White
Harrison White
Harrison Colyar White is the emeritus Giddings Professor of Sociology at Columbia University. White is an influential scholar in the domain of social networks. He is credited with the development of a number of mathematical models of social structure including vacancy chains and blockmodels...

 and his students at the Harvard University Department of Social Relations
Harvard Department of Social Relations
The Department of Social Relations for Interdisciplinary Social Science Studies, more commonly known as the "Department of Social Relations" was an interdisciplinary collaboration among three of the social science departments at Harvard University beginning in 1946...

: Ivan Chase, Bonnie Erickson, Harriet Friedmann, Mark Granovetter
Mark Granovetter
Professor Mark Granovetter is an American sociologist at Stanford University who has created theories in modern sociology since the 1970s. He is best known for his work in social network theory and in economic sociology, particularly his theory on the spread of information in social networks known...

, Nancy Howell, Joel Levine, Nicholas Mullins, John Padgett, Michael Schwartz
Michael Schwartz (sociologist)
Michael Schwartz is an American sociologist and prominent critic of the Iraq war. He is Professor of Sociology at the State University of New York at Stony Brook in New York, where he also serves as faculty director of the Undergraduate College of Global Studies and Chair of the Sociology...

 and Barry Wellman
Barry Wellman
Barry Wellman, FRSC directs NetLab as the S.D. Clark Professor of Sociology at the University of Toronto. His areas of research are community sociology, the Internet, human-computer interaction and social structure, as manifested in social networks in communities and organizations...

. Also independently active in the Harvard Social Relations department at the time were Charles Tilly, who focused on networks in political and community sociology and social movements, and Stanley Milgram, who developed the "six degrees of separation" thesis. Mark Granovetter
Mark Granovetter
Professor Mark Granovetter is an American sociologist at Stanford University who has created theories in modern sociology since the 1970s. He is best known for his work in social network theory and in economic sociology, particularly his theory on the spread of information in social networks known...

 and Barry Wellman
Barry Wellman
Barry Wellman, FRSC directs NetLab as the S.D. Clark Professor of Sociology at the University of Toronto. His areas of research are community sociology, the Internet, human-computer interaction and social structure, as manifested in social networks in communities and organizations...

 are among the former students of White who have elaborated and popularized social network analysis.

Significant independent work was also done by scholars elsewhere: University of California Irvine social scientists interested in mathematical applications, centered around Linton Freeman, including John Boyd, Susan Freeman, Kathryn Faust, A. Kimball Romney
A. Kimball Romney
A. Kimball Romney is a social sciences professor and one of the founders of cognitive anthropology. He spent most of his career at the University of California, Irvine....

 and Douglas White; quantitative analysts at the University of Chicago
University of Chicago
The University of Chicago is a private research university in Chicago, Illinois, USA. It was founded by the American Baptist Education Society with a donation from oil magnate and philanthropist John D. Rockefeller and incorporated in 1890...

, including Joseph Galaskiewicz, Wendy Griswold, Edward Laumann, Peter Marsden, Martina Morris, and John Padgett; and communication scholars at Michigan State University
Michigan State University
Michigan State University is a public research university in East Lansing, Michigan, USA. Founded in 1855, it was the pioneer land-grant institution and served as a model for future land-grant colleges in the United States under the 1862 Morrill Act.MSU pioneered the studies of packaging,...

, including Nan Lin
Nan Lin
Nan Lin is the Oscar L. Tang Family Professor of Sociology of the Trinity College, Duke University. He is most notable for his research and writing on social networks and social capital.-Biography:...

 and Everett Rogers
Everett Rogers
Everett M. Rogers was a communication scholar, sociologist, writer, and teacher. He is best known for originating the diffusion of innovations theory and for introducing the term early adopter....

. A substantively-oriented University of Toronto
University of Toronto
The University of Toronto is a public research university in Toronto, Ontario, Canada, situated on the grounds that surround Queen's Park. It was founded by royal charter in 1827 as King's College, the first institution of higher learning in Upper Canada...

 sociology group developed in the 1970s, centered on former students of Harrison White: S.D. Berkowitz, Harriet Friedmann, Nancy Leslie Howard, Nancy Howell, Lorne Tepperman and Barry Wellman
Barry Wellman
Barry Wellman, FRSC directs NetLab as the S.D. Clark Professor of Sociology at the University of Toronto. His areas of research are community sociology, the Internet, human-computer interaction and social structure, as manifested in social networks in communities and organizations...

, and also including noted modeler and game theorist
Game theory
Game theory is a mathematical method for analyzing calculated circumstances, such as in games, where a person’s success is based upon the choices of others...

 Anatol Rapoport
Anatol Rapoport
Anatol Rapoport was a Russian-born American Jewish mathematical psychologist. He contributed to general systems theory, mathematical biology and to the mathematical modeling of social interaction and stochastic models of contagion.-Biography:...

. In terms of theory, it critiqued methodological individualism and group-based analyses, arguing that seeing the world as social networks offered more analytic leverage.

Research


Social network analysis has been used in epidemiology
Epidemiology
Epidemiology is the study of health-event, health-characteristic, or health-determinant patterns in a population. It is the cornerstone method of public health research, and helps inform policy decisions and evidence-based medicine by identifying risk factors for disease and targets for preventive...

 to help understand how patterns of human contact aid or inhibit the spread of diseases such as HIV in a population. The evolution of social networks can sometimes be modeled by the use of agent based models, providing insight into the interplay between communication rules, rumor
Rumor
A rumor or rumour is often viewed as "an unverified account or explanation of events circulating from person to person and pertaining to an object, event, or issue in public concern" However, a review of the research on rumor conducted by Pendleton in 1998 found that research across sociology,...

 spreading and social structure.

SNA may also be an effective tool for mass surveillance
Mass surveillance
Mass surveillance is the pervasive surveillance of an entire population, or a substantial fraction thereof.Modern governments today commonly perform mass surveillance of their citizens, explaining that they believe that it is necessary to protect them from dangerous groups such as terrorists,...

 – for example the Total Information Awareness program was doing in-depth research on strategies to analyze social networks to determine whether or not U.S. citizens were political threats.

Diffusion of innovations
Diffusion of innovations
Diffusion of Innovations is a theory that seeks to explain how, why, and at what rate new ideas and technology spread through cultures. Everett Rogers, a professor of rural sociology, popularized the theory in his 1962 book Diffusion of Innovations...

 theory explores social networks and their role in influencing the spread of new ideas and practices. Change agents and opinion leaders often play major roles in spurring the adoption of innovations, although factors inherent to the innovations also play a role.

Robin Dunbar
Robin Dunbar
Robin Ian MacDonald Dunbar is a British anthropologist and evolutionary psychologist and a specialist in primate behaviour. He is currently Professor of Evolutionary Anthropology and the Director of the Institute of Cognitive and Evolutionary Anthropology of the University of Oxford and the...

 has suggested that the typical size of an egocentric network is constrained to about 150 members due to possible limits in the capacity of the human communication channel. The rule arises from cross-cultural studies in sociology
Sociology
Sociology is the study of society. It is a social science—a term with which it is sometimes synonymous—which uses various methods of empirical investigation and critical analysis to develop a body of knowledge about human social activity...

 and especially anthropology
Anthropology
Anthropology is the study of humanity. It has origins in the humanities, the natural sciences, and the social sciences. The term "anthropology" is from the Greek anthrōpos , "man", understood to mean mankind or humanity, and -logia , "discourse" or "study", and was first used in 1501 by German...

 of the maximum size of a village
Village
A village is a clustered human settlement or community, larger than a hamlet with the population ranging from a few hundred to a few thousand , Though often located in rural areas, the term urban village is also applied to certain urban neighbourhoods, such as the West Village in Manhattan, New...

 (in modern parlance most reasonably understood as an ecovillage
Ecovillage
Ecovillages are intentional communities with the goal of becoming more socially, economically and ecologically sustainable. Some aim for a population of 50–150 individuals. Larger ecovillages of up to 2,000 individuals exist as networks of smaller subcommunities to create an ecovillage model that...

). It is theorized in evolutionary psychology
Evolutionary psychology
Evolutionary psychology is an approach in the social and natural sciences that examines psychological traits such as memory, perception, and language from a modern evolutionary perspective. It seeks to identify which human psychological traits are evolved adaptations, that is, the functional...

 that the number
Dunbar's number
Dunbar's number is suggested to be a theoretical cognitive limit to the number of people with whom one can maintain stable social relationships. These are relationships in which an individual knows who each person is, and how each person relates to every other person...

 may be some kind of limit of average human ability to recognize members and track emotional facts about all members of a group. However, it may be due to economics
Economics
Economics is the social science that analyzes the production, distribution, and consumption of goods and services. The term economics comes from the Ancient Greek from + , hence "rules of the house"...

 and the need to track "free riders
Free rider problem
In economics, collective bargaining, psychology, and political science, a free rider is someone who consumes a resource without paying for it, or pays less than the full cost. The free rider problem is the question of how to limit free riding...

", as it may be easier in larger groups to take advantage of the benefits of living in a community without contributing to those benefits.

Mark Granovetter
Mark Granovetter
Professor Mark Granovetter is an American sociologist at Stanford University who has created theories in modern sociology since the 1970s. He is best known for his work in social network theory and in economic sociology, particularly his theory on the spread of information in social networks known...

 found in one study that more numerous weak ties can be important in seeking information and innovation. Clique
Clique
A clique is an exclusive group of people who share common interests, views, purposes, patterns of behavior, or ethnicity. A clique as a reference group can be either normative or comparative. Membership in a clique is typically exclusive, and qualifications for membership may be social or...

s have a tendency to have more homogeneous opinions as well as share many common traits. This homophilic
Homophily
Homophily is the tendency of individuals to associate and bond with similar others. The presence of homophily has been discovered in a vast array of network studies. Within their extensive review paper, sociologists McPherson, Smith-Lovin and Cook cite over one hundred studies that have observed...

 tendency was the reason for the members of the cliques to be attracted together in the first place. However, being similar, each member of the clique would also know more or less what the other members knew. To find new information or insights, members of the clique will have to look beyond the clique to its other friends and acquaintances. This is what Granovetter called "the strength of weak ties".

Guanxi
Guanxi
Guanxi describes the basic dynamic in personalized networks of influence, and is a central idea in Chinese society. In Western media, the pinyin romanization of this Chinese word is becoming more widely used instead of the two common translations—"connections" and "relationships"—as neither of...

 (关系)is a central concept in Chinese society (and other East Asian cultures) that can be summarized as the use of personal influence. The word is usually translated as "relation," "connection" or "tie" and is used in as broad a variety of contexts as are its English counterparts. However, in the context of interpersonal relations, Guanxi
Guanxi
Guanxi describes the basic dynamic in personalized networks of influence, and is a central idea in Chinese society. In Western media, the pinyin romanization of this Chinese word is becoming more widely used instead of the two common translations—"connections" and "relationships"—as neither of...

 (关系)is loosely analogous to "clout" or "pull" in the West. Guanxi can be studied from a social network approach.

The small world phenomenon is the hypothesis
Hypothesis
A hypothesis is a proposed explanation for a phenomenon. The term derives from the Greek, ὑποτιθέναι – hypotithenai meaning "to put under" or "to suppose". For a hypothesis to be put forward as a scientific hypothesis, the scientific method requires that one can test it...

 that the chain of social acquaintances required to connect one arbitrary person to another arbitrary person anywhere in the world is generally short. The concept gave rise to the famous phrase six degrees of separation
Six degrees of separation
Six degrees of separation refers to the idea that everyone is on average approximately six steps away, by way of introduction, from any other person on Earth, so that a chain of, "a friend of a friend" statements can be made, on average, to connect any two people in six steps or fewer...

 after a 1967 small world experiment by psychologist Stanley Milgram
Stanley Milgram
Stanley Milgram was an American social psychologist most notable for his controversial study known as the Milgram Experiment. The study was conducted in the 1960s during Milgram's professorship at Yale...

. In Milgram's experiment, a sample of US individuals were asked to reach a particular target person by passing a message along a chain of acquaintances. The average length of successful chains turned out to be about five intermediaries or six separation steps (the majority of chains in that study actually failed to complete). The methods (and ethics as well) of Milgram's experiment were later questioned by an American scholar, and some further research to replicate Milgram's findings found that the degrees of connection needed could be higher. Academic researchers continue to explore this phenomenon as Internet-based communication technology has supplemented the phone and postal systems available during the times of Milgram. A recent electronic small world experiment at Columbia University
Columbia University
Columbia University in the City of New York is a private, Ivy League university in Manhattan, New York City. Columbia is the oldest institution of higher learning in the state of New York, the fifth oldest in the United States, and one of the country's nine Colonial Colleges founded before the...

 found that about five to seven degrees of separation are sufficient for connecting any two people through e-mail.

Collaboration graph
Collaboration graph
In mathematics and social science, a collaboration graph is a graph modeling some social network where the vertices represent participants of that network and where two distinct participants are joined by an edge whenever there is a collaborative relationship between them of a particular kind...

s 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
Cycle (graph theory)
In graph theory, the term cycle may refer to a closed path. If repeated vertices are allowed, it is more often called a closed walk. If the path is a simple path, with no repeated vertices or edges other than the starting and ending vertices, it may also be called a simple cycle, circuit, circle,...

 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 balances and unbalanced cycles, the evolution of sign
Sign
A sign is something that implies a connection between itself and its object. A natural sign bears a causal relation to its object—for instance, thunder is a sign of storm. A conventional sign signifies by agreement, as a full stop signifies the end of a sentence...

ed social network graphs can be predicted.

One study has found that happiness
Happiness
Happiness is a mental state of well-being characterized by positive emotions ranging from contentment to intense joy. A variety of biological, psychological, religious, and philosophical approaches have striven to define happiness and identify its sources....

 tends to be correlated in social networks. When a person is happy, nearby friends have a 25 percent higher chance of being happy themselves. Furthermore, people at the center of a social network tend to become happier in the future than those at the periphery. Clusters of happy and unhappy people were discerned within the studied networks, with a reach of three degrees of separation: a person's happiness was associated with the level of happiness of their friends' friends' friends. (See also Emotional contagion
Emotional contagion
Emotional contagion is the tendency to catch and feel emotions that are similar to and influenced by those of others. One view developed by John Cacioppo of the underlying mechanism is that it represents a tendency to automatically mimic and synchronize facial expressions, vocalizations, postures,...

.)

Some researchers have suggested that human social networks may have a genetic basis. Using a sample of twins from the National Longitudinal Study of Adolescent Health
National Longitudinal Study of Adolescent Health
The National Longitudinal Study of Adolescent Health is the only nationally representative study of adolescent sexuality, which has spawned over one thousand peer-reviewed publications on many issues related to adolescent health and sexuality, and other adolescent health risk behaviors.The Add...

, they found that in-degree (the number of times a person is named as a friend), transitivity (the probability that two friends are friends with one another), and betweenness centrality (the number of paths in the network that pass through a given person) are all significantly heritable. Existing models of network formation cannot account for this intrinsic node variation, so the researchers propose an alternative "Attract and Introduce" model that can explain heritability and many other features of human social networks.

Metrics (measures) in social network analysis


Betweenness: The extent to which a node lies between other nodes in the network. This measure takes into account the connectivity of the node's neighbors, giving a higher value for nodes which bridge clusters. The measure reflects the number of people who a person is connecting indirectly through their direct links.

Bridge
Bridge (graph theory)
In graph theory, a bridge is an edge whose deletion increases the number of connected components. Equivalently, an edge is a bridge if and only if it is not contained in any cycle....

: An edge is said to be a bridge if deleting it would cause its endpoints to lie in different components of a graph.

Centrality
Centrality
Within graph theory and network analysis, there are various measures of the centrality of a vertex within a graph that determine the relative importance of a vertex within the graph...

: This measure gives a rough indication of the social power of a node based on how well they "connect" the network. "Betweenness," "Closeness," and "Degree" are all measures of centrality.

Centralization
Centralization
Centralisation, or centralization , is the process by which the activities of an organisation, particularly those regarding planning and decision-making, become concentrated within a particular location and/or group....

: The difference between the number of links for each node divided by maximum possible sum of differences. A centralized network will have many of its links dispersed around one or a few nodes, while a decentralized network is one in which there is little variation between the number of links each node possesses.

Closeness: The degree an individual is near all other individuals in a network (directly or indirectly). It reflects the ability to access information through the "grapevine
Grapevine (gossip)
To hear something through the grapevine is to learn of something informally and unofficially by means of gossip and rumor.The usual implication is that the information was passed person to person by word of mouth, perhaps in a confidential manner among friends or colleagues. It can also imply an...

" of network members. Thus, closeness is the inverse of the sum of the shortest distances between each individual and every other person in the network. (See also: Proxemics
Proxemics
Proxemics is the study of measurable distances between people as they interact. The term was introduced by anthropologist Edward T. Hall in 1966...

) The shortest path may also be known as the "geodesic distance."

Clustering coefficient
Clustering coefficient
In graph theory, a clustering coefficient is a measure of degree to which nodes in a graph tend to cluster together. Evidence suggests that in most real-world networks, and in particular social networks, nodes tend to create tightly knit groups characterised by a relatively high density of ties...

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

Cohesion: The degree to which actors are connected directly to each other by cohesive bonds
Social cohesion
Social cohesion is a term used in social policy, sociology and political science to describe the bonds or "glue" that bring people together in society, particularly in the context of cultural diversity. Social cohesion is a multi-faceted notion covering many different kinds of social phenomena...

. Groups are identified as ‘clique
Clique
A clique is an exclusive group of people who share common interests, views, purposes, patterns of behavior, or ethnicity. A clique as a reference group can be either normative or comparative. Membership in a clique is typically exclusive, and qualifications for membership may be social or...

s’ if every individual is directly tied to every other individual, ‘social circle
Social circle
Social circles are groups of socially interconnected people. A Social circle is distinguished from a social pyramid in that there are two perspectives that can be used to describe a social circle: the perspective of an individual who is the locus of a particular group of socially interconnected...

s’ if there is less stringency of direct contact, which is imprecise, or as structurally cohesive
Structural cohesion
Structural cohesion is the sociological conception of cohesion in social groups. It is defined as the minimal number of actors in a social network that need to be removed to disconnect at least two actors in the remaining group. It is thus identical to the question of the node connectivity of a...

 blocks if precision is wanted.

Degree: The count of the number of ties to other actors in the network. See also degree (graph theory)
Degree (graph theory)
In graph theory, the degree of a vertex of a graph is the number of edges incident to the vertex, with loops counted twice. The degree of a vertex v is denoted \deg. The maximum degree of a graph G, denoted by Δ, and the minimum degree of a graph, denoted by δ, are the maximum and minimum degree...

.

(Individual-level) Density
Dense graph
In mathematics, a dense graph is a graph in which the number of edges is close to the maximal number of edges. The opposite, a graph with only a few edges, is a sparse graph...

: The degree a respondent's ties know one another/ proportion of ties among an individual's nominees. Network or global-level density is the proportion of ties in a network relative to the total number possible (sparse versus dense networks).

Efficient immunization strategy: The acquaintance immunization strategy, propose to immunize friends of randomly selected nodes. It is found to be very efficient compared to random immunization.

Flow betweenness centrality: The degree that a node contributes to sum of maximum flow between all pairs of nodes (not that node).

Eigenvector centrality: A measure of the importance of a node
Vertex (graph theory)
In graph theory, a vertex or node is the fundamental unit out of which graphs are formed: an undirected graph consists of a set of vertices and a set of edges , while a directed graph consists of a set of vertices and a set of arcs...

 in a network. It assigns relative scores to all nodes in the network based on the principle that connections to nodes having a high score contribute more to the score of the node in question.

Human interaction: Links in social networks are formed through human interactions. Scaling laws in human interaction activity were found by Rybski et al.

Influential Spreaders: A method to identify influential spreaders is described by Kitsak et al.

Local bridge: An edge is a local bridge if its endpoints share no common neighbors. Unlike a bridge, a local bridge is contained in a cycle.

Path length: The distances between pairs of nodes in the network. Average path-length is the average of these distances between all pairs of nodes.

Prestige: In a directed graph prestige is the term used to describe a node's centrality. "Degree Prestige," "Proximity Prestige," and "Status Prestige" are measures of Prestige. See also degree (graph theory)
Degree (graph theory)
In graph theory, the degree of a vertex of a graph is the number of edges incident to the vertex, with loops counted twice. The degree of a vertex v is denoted \deg. The maximum degree of a graph G, denoted by Δ, and the minimum degree of a graph, denoted by δ, are the maximum and minimum degree...

.

Radiality: Degree an individual’s network reaches out into the network and provides novel information and influence.

Reach: The degree any member of a network can reach other members of the network.

Second order centrality: It assigns relative scores to all nodes in the network based on the observation that important nodes see a random walk
Random walk
A random walk, sometimes denoted RW, is a mathematical formalisation of a trajectory that consists of taking successive random steps. For example, the path traced by a molecule as it travels in a liquid or a gas, the search path of a foraging animal, the price of a fluctuating stock and the...

 (running on the network) "more regularly" than other nodes.

Structural cohesion
Structural cohesion
Structural cohesion is the sociological conception of cohesion in social groups. It is defined as the minimal number of actors in a social network that need to be removed to disconnect at least two actors in the remaining group. It is thus identical to the question of the node connectivity of a...

: The minimum number of members who, if removed from a group, would disconnect the group. The relation between fragmentation (Structural cohesion) and percolation theory is discussed by Li et al.

Structural equivalence
Equivalence relation
In mathematics, an equivalence relation is a relation that, loosely speaking, partitions a set so that every element of the set is a member of one and only one cell of the partition. Two elements of the set are considered equivalent if and only if they are elements of the same cell...

: Refers to the extent to which nodes have a common set of linkages to other nodes in the system. The nodes don’t need to have any ties to each other to be structurally equivalent.

Structural hole: Static holes that can be strategically filled by connecting one or more links to link together other points. Linked to ideas of social capital
Social capital
Social capital is a sociological concept, which refers to connections within and between social networks. The concept of social capital highlights the value of social relations and the role of cooperation and confidence to get collective or economic results. The term social capital is frequently...

: if you link to two people who are not linked you can control their communication.

Network analytic software



Network analytic tools are used to represent the nodes (agents) and edges (relationships) in a network, and to analyze the network data. Like other software tools, the data can be saved in external files. Additional information comparing the various data input formats used by network analysis software packages is available at NetWiki. Network analysis tools allow researchers to investigate large networks like the Internet, disease transmission, etc. These tools provide mathematical functions that can be applied to the network model.

Visualization of networks


Visual representation of social networks is important to understand the network data and convey the result of the analysis http://www.cmu.edu/joss/content/articles/volume1/Freeman.html. 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.

Typical representation of the network data are graphs in network layout (nodes and ties). These are not very easy-to-read and do not allow an intuitive interpretation. Various new methods have been developed in order to display network data in more intuitive format (e.g. Sociomapping
Sociomapping
Sociomapping is a method developed for processing and visualization of relational data . It uses the data-landscape metaphor, creating a visually coded picture resembling a map that can be interpreted with similar rules as navigation in the landscape...

).

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. One benefit of this approach is that it allows researchers to collect qualitative data and ask clarifying questions while the network data is collected. Examples of network mapping techniques are Net-Map
Net-Map Toolbox
The net-map toolbox is a social network analysis tool that uses interviews and mapping to help people understand, visualize, discuss, and improve situations in which many different actors influence outcomes. Social network analysis is a research approach used by scholars such as S.D...

 (pen-and-paper based) and VennMaker (digital).

Patents


There has been rapid growth in the number of US patent applications that cover new technologies related to social networking. The number of published applications has been growing at about 250% per year over the past five years. There are now over 2000 published applications. Only about 100 of these applications have been issued as patents, however, largely due to the multi-year backlog in examination of business method patents.

See also


  • Complex Network
    Complex network
    In the context of network theory, a complex network is a graph with non-trivial topological features—features that do not occur in simple networks such as lattices or random graphs but often occur in real graphs...

  • Clique
    Clique
    A clique is an exclusive group of people who share common interests, views, purposes, patterns of behavior, or ethnicity. A clique as a reference group can be either normative or comparative. Membership in a clique is typically exclusive, and qualifications for membership may be social or...

  • Community of practice
    Community of practice
    A community of practice is, according to cognitive anthropologists Jean Lave and Etienne Wenger, a group of people who share an interest, a craft, and/or a profession. The group can evolve naturally because of the members' common interest in a particular domain or area, or it can be created...

  • Dynamic network analysis
    Dynamic Network Analysis
    Dynamic network analysis is an emergent scientific field that brings together traditional social network analysis , link analysis and multi-agent systems within network science and network theory. There are two aspects of this field. The first is the statistical analysis of DNA data. The second...

  • Digital footprint
    Digital footprint
    A digital footprint is a trail left by an entity's interactions in a digital environment; including their usage of TV, mobile phone, internet and world wide web, mobile web and other devices and sensors...

  • FOAF (software)
    FOAF (software)
    FOAF is a machine-readable ontology describing persons, their activities and their relations to other people and objects. Anyone can use FOAF to describe him or herself...

     (Friend of a friend)
  • Friendship paradox
    Friendship paradox
    The friendship paradox is the phenomenon first observed by the sociologist Scott L. Feld in 1991 that most people have fewer friends than their friends have, on average. It can be explained as a form of sampling bias in which people with greater numbers of friends have an increased likelihood of...

  • Graph theory
    Graph theory
    In mathematics and computer science, graph theory is the study of graphs, mathematical structures used to model pairwise relations between objects from a certain collection. A "graph" in this context refers to a collection of vertices or 'nodes' and a collection of edges that connect pairs of...

  • Knowledge management
    Knowledge management
    Knowledge management comprises a range of strategies and practices used in an organization to identify, create, represent, distribute, and enable adoption of insights and experiences...

  • List of social networking websites
  • List of virtual communities with more than 100 million users
  • Mathematical sociology
    Mathematical sociology
    Mathematical sociology is the usage of mathematics to construct social theories. Mathematical sociology aims to take sociological theory, which is strong in intuitive content but weak from a formal point of view, and to express it in formal terms...

  • Metcalfe's Law
    Metcalfe's law
    Metcalfe's law states that the value of a telecommunications network is proportional to the square of the number of connected usersof the system...

  • Network of practice
    Network of practice
    Network of Practice is a concept originated by John Seely Brown and Paul Duguid . This concept, related to the work on communities of practice by Jean Lave and Etienne Wenger, refers to the overall set of various types of informal, emergent social networks that facilitate information exchange...

  • Network science
    Network science
    Network science is a new and emerging scientific discipline that examines the interconnections among diverse physical or engineered networks, information networks, biological networks, cognitive and semantic networks, and social networks. This field of science seeks to discover common principles,...

  • Organizational patterns
    Organizational patterns
    Organizational patterns are recurring structures of relationship, usually in a professional organization, that help the organization achieve its goals....

  • Percolation theory
    Percolation theory
    In mathematics, percolation theory describes the behavior of connected clusters in a random graph. The applications of percolation theory to materials science and other domains are discussed in the article percolation.-Introduction:...

  • Personal Network
    Personal Network
    A Personal Network is a set of human contacts known to an individual, with whom that individual would expect to interact at intervals to support a given set of activities....

  • Scale free network
  • Small world network

  • Small world phenomenon
  • Social data revolution
    Social data revolution
    -Overview:The Social Data Revolution is the shift in human communication patterns towards increased personal information sharing and its related implications, made possible by the rise of social networks in early 2000s...

  • Social-circles network model
    Social-circles network model
    The generative model of feedback networks , studied by White, Kejžar, Tsallis, Farmer, or social-circles network model, defines a class of random graphs generated by simple processes that are common to edge formation and feedback loops in social circles...

  • Social network aggregation
    Social network aggregation
    Social network aggregation is the process of collecting content from multiple social network services, such as MySpace or Facebook. The task is often performed by a social network aggregator, which pulls together information into a single location, or helps a user consolidate multiple social...

  • Social network analysis software
    Social network analysis software
    Social network analysis software facilitates quantitative or qualitative analysis of social networks, by describing features of a network, either through numerical or visual representation...

  • Social networking service
  • Social engine
    Social engine
    A social engine is a hybrid between a Social Network and a Search Engine.The term social engine is the shortened version of the term social networking engine which provides a software development framework for developing social applications and a platform for hosting them...

  • Social software
    Social software
    Social software applications include communication tools and interactive tools. Communication tools typically handle the capturing, storing and presentation of communication, usually written but increasingly including audio and video as well. Interactive tools handle mediated interactions between a...

  • Social unit
    Social unit
    Social unit is a term used in sociology, anthropology, ethnology, and also in animal behaviour studies, zoology and biology to describe a social entity which is part of and participates in a larger social group or society....

  • Social web
    Social Web
    The social Web is a set of social relations that link people through the World Wide Web. The Social web encompasses how websites and software are designed and developed in order to support and foster social interaction. These online social interactions form the basis of much online activity...

  • SocialRank
    SocialRank
    SocialRank is an algorithm that assigns a numerical weighting to each node in a Social Network, with the purpose of measuring this node's - or this person's - relative importance or influence within the network....

  • Sociomapping
    Sociomapping
    Sociomapping is a method developed for processing and visualization of relational data . It uses the data-landscape metaphor, creating a visually coded picture resembling a map that can be interpreted with similar rules as navigation in the landscape...

  • Socio-technical systems
    Socio-technical systems
    Sociotechnical systems in organizational development is an approach to complex organizational work design that recognizes the interaction between people and technology in workplaces. The term also refers to the interaction between society's complex infrastructures and human behaviour...

  • Surveillance
    Surveillance
    Surveillance is the monitoring of the behavior, activities, or other changing information, usually of people. It is sometimes done in a surreptitious manner...

  • Triadic closure
    Triadic closure
    Triadic closure is a concept in social network theory, first suggested by German sociologist Georg Simmel in the early 1900s. Triadic closure is the property among 3 nodes A, B, and C, such that if a strong tie exists between A-B and A-C, there is a weak or strong tie between B-C...

  • Value network
    Value network
    A value network is a business analysis perspective that describes social and technical resources within and between businesses. The nodes in a value network represent people . The nodes are connected by interactions that represent tangible and intangible deliverables. These deliverables take the...

  • Virtual community
    Virtual community
    A virtual community is a social network of individuals who interact through specific media, potentially crossing geographical and political boundaries in order to pursue mutual interests or goals...

  • Virtual organization
    Virtual organization
    Several unrelated things are named virtual organization:* In business an organization that can take one of the following forms:** a business which operates primarily via electronic means; see virtual business...

  • Weighted network
    Weighted network
    A weighted network is a network where the ties among nodes have weights assigned to them. A network is a system whose elements are somehow connected . The elements of a system are represented as nodes and the connections among interacting elements are known as ties, edges, arcs, or links...


Further reading

  • Barnes, J. A. "Class and Committees in a Norwegian Island Parish", Human Relations 7:39–58
  • Berkowitz, Stephen D. 1982. An Introduction to Structural Analysis: The Network Approach to Social Research. Toronto: Butterworth. ISBN 0-409-81362-1
  • Brandes, Ulrik, and Thomas Erlebach (Eds.). 2005. Network Analysis: Methodological Foundations Berlin, Heidelberg: Springer-Verlag.
  • Breiger, Ronald L. 2004. "The Analysis of Social Networks." Pp. 505–526 in Handbook of Data Analysis, edited by Melissa Hardy and Alan Bryman. London: Sage Publications. ISBN 0-7619-6652-8 Excerpts in pdf format
  • Burt, Ronald S. (1992). Structural Holes: The Structure of Competition. Cambridge, MA: Harvard University Press. ISBN 0-674-84372-X Casaleggio, Davide (2008). TU SEI RETE. La Rivoluzione del business, del marketing e della politica attraverso le reti sociali. ISBN 88-901826-5-2
  • Carrington, Peter J., John Scott and Stanley Wasserman (Eds.). 2005. Models and Methods in Social Network Analysis. New York: Cambridge University Press. ISBN 978-0-521-80959-7
  • Christakis, Nicholas
    Nicholas A. Christakis
    Nicholas A. Christakis is a Greek American physician and sociologist known for his research on social networks and on the socioeconomic and biosocial determinants of health, longevity, and behavior...

     and James H. Fowler
    James H. Fowler
    James H. Fowler is an American social scientist specializing in social networks, cooperation, political participation, and genopolitics...

     "The Spread of Obesity in a Large Social Network Over 32 Years," New England Journal of Medicine 357 (4): 370–379 (26 July 2007)
  • Doreian, Patrick, Vladimir Batagelj, and Anuška Ferligoj. (2005). Generalized Blockmodeling. Cambridge: Cambridge University Press. ISBN 0-521-84085-6
  • Freeman, Linton C. (2004) The Development of Social Network Analysis: A Study in the Sociology of Science. Vancouver: Empirical Press. ISBN 1-59457-714-5
  • Hill, R. and Dunbar, R. 2002. "Social Network Size in Humans." Human Nature, Vol. 14, No. 1, pp. 53–72. pdf
  • Huisman, M. and Van Duijn, M. A. J. (2005). Software for Social Network Analysis. In P J. Carrington, J. Scott, & S. Wasserman (Editors), Models and Methods in Social Network Analysis (pp. 270–316). New York: Cambridge University Press. ISBN 978-0-521-80959-7
  • Krebs, Valdis (2006) Social Network Analysis, A Brief Introduction. (Includes a list of recent SNA applications Web Reference.)
  • Ligon, Ethan; Schechter, Laura, "The Value of Social Networks in rural Paraguay", University of California, Berkeley, Seminar, March 25, 2009, Department of Agricultural & Resource Economics, College of Natural Resources, University of California, Berkeley
  • Lima, Francisco W. S., Hadzibeganovic, Tarik, and Dietrich Stauffer (2009). Evolution of ethnocentrism on undirected and directed Barabási-Albert networks. Physica A, 388(24), 4999–5004.
  • Lin, Nan, Ronald S. Burt and Karen Cook, eds. (2001). Social Capital: Theory and Research. New York: Aldine de Gruyter. ISBN 0-202-30643-7
  • Mullins, Nicholas. 1973. Theories and Theory Groups in Contemporary American Sociology. New York: Harper and Row. ISBN 0-06-044649-8
  • Müller-Prothmann, Tobias (2006): Leveraging Knowledge Communication for Innovation. Framework, Methods and Applications of Social Network Analysis in Research and Development, Frankfurt a. M. et al.: Peter Lang, ISBN 0-8204-9889-0. via JSTOR
    JSTOR
    JSTOR is an online system for archiving academic journals, founded in 1995. It provides its member institutions full-text searches of digitized back issues of several hundred well-known journals, dating back to 1665 in the case of the Philosophical Transactions of the Royal Society...

  • Moody, James, and Douglas R. White (2003). "Structural Cohesion and Embeddedness: A Hierarchical Concept of Social Groups." American Sociological Review 68(1):103–127. http://www2.asanet.org/journals/ASRFeb03MoodyWhite.pdf pdf
  • Nohria, Nitin
    Nitin Nohria
    Nitin Nohria is the 10th and the current dean of Harvard Business School. He is also the George F. Baker Professor of Business Administration, co-chair of the HBS Leadership Initiative and sits on the executive committee of the University's interfaculty initiative on advanced leadership.Over the...

     and Robert Eccles (1992). Networks in Organizations. second ed. Boston: Harvard Business Press. ISBN 0-87584-324-7
  • Nooy, Wouter d., A. Mrvar and Vladimir Batagelj. (2005). Exploratory Social Network Analysis with Pajek. Cambridge: Cambridge University Press. ISBN 0-521-84173-9
  • Scott, John. (2000). Social Network Analysis: A Handbook. 2nd Ed. Newberry Park, CA: Sage. ISBN 0-7619-6338-3
  • Sethi, Arjun. (2008). Valuation of Social Networking http://fusion.dalmatech.com/%7Eadmin24/files/socialnetworkvaluation.pdf
  • Tilly, Charles. (2005). Identities, Boundaries, and Social Ties. Boulder, CO: Paradigm press. ISBN 1-59451-131-4
  • Valente, Thomas W. (1995). Network Models of the Diffusion of Innovations. Cresskill, NJ: Hampton Press. ISBN 1-881303-21-7
  • Wasserman, Stanley, & Faust, Katherine. (1994). Social Network Analysis: Methods and Applications. Cambridge: Cambridge University Press. ISBN 0-521-38269-6
  • Watkins, Susan Cott. (2003). "Social Networks." Pp. 909–910 in Encyclopedia of Population. rev. ed. Edited by Paul George Demeny and Geoffrey McNicoll. New York: Macmillan Reference. ISBN 0-02-865677-6
  • Watts, Duncan J. (2003). Small Worlds: The Dynamics of Networks between Order and Randomness. Princeton: Princeton University Press. ISBN 0-691-11704-7
  • Watts, Duncan J. (2004). Six Degrees: The Science of a Connected Age. W. W. Norton & Company. ISBN 0-393-32542-3
  • Wellman, Barry (1998). Networks in the Global Village: Life in Contemporary Communities. Boulder, CO: Westview Press. ISBN 0-8133-1150-0
  • Wellman, Barry. 2001. "Physical Place and Cyber-Place: Changing Portals and the Rise of Networked Individualism." International Journal for Urban and Regional Research 25 (2): 227–52.
  • Wellman, Barry and Berkowitz, Stephen D. (1988). Social Structures: A Network Approach. Cambridge: Cambridge University Press. ISBN 0-521-24441-2
  • Weng, M. (2007). A Multimedia Social-Networking Community for Mobile Devices Interactive Telecommunications Program, Tisch School of the Arts/ New York University
  • White, Harrison, Scott Boorman and Ronald Breiger. 1976. "Social Structure from Multiple Networks: I Blockmodels of Roles and Positions." American Journal of Sociology 81: 730–80.

External links