Social Network Analysis

Social network analysis, often abbreviated SNA, is a way of investigating social structures with networks and graph theory. It describes a structure as nodes, which are individual actors, people or things, and the ties, edges or links, which are the relationships or interactions connecting them. Typical subjects include friendship and acquaintance networks, business networks, kinship, information circulation and disease transmission, and the results are often drawn as sociograms in which nodes are points and ties are lines. Its theoretical roots lie in the work of early sociologists such as Georg Simmel and Emile Durkheim on patterns of relationships. Jacob Moreno and Helen Jennings introduced basic analytical methods in 1934, and John Arundel Barnes used the term systematically in 1954. From the 1970s scholars including Mark Granovetter and Harrison White expanded its use, and measures such as density, centrality, homophily and cohesion are now standard. It has become a key technique in sociology and is also used in anthropology, public health, economics and computer science.