Social network analysis (SNA) focuses on the structure of ties within a set of social actors, e.g., persons, groups, organizations,
and nations, or the products of human activity or cognition such as web sites, semantic concepts, and so on. It is linked
to structuralism in sociology stressing the significance of relations among social actors to their behaviour, opinions, and
attitudes. Social network analysis is felt to be appropriate for analyzing social cohesion, brokerage and exchange, as well
as social ranking within or among social groups.
Two perspectives dominate SNA: the socio-centred and ego-centred perspective.
The socio-centred perspective analyses overall network structure. It looks for patterns of ties that indicate cohesive social
groups, central actors that may be paramount to the integration of the social network, and asymmetries that may reflect social
prestige or social stratification. Recent advances are found primarily in the technique of blockmodelling. The ego-centred
perspective focuses on the composition of local network structure. Do actors influence one another through their network ties
(social influence model) and/or do actors adjust their ties to the characteristics of their peers and to their ties with them
(social selection model)? Recent advances in this area include new types of statistical models.
The development and interest
in SNA has increased sharply over the last few decades due to the application of mathematics - notably graph theory and statistical
models - and the wide availability of software for network analysis both commercial and freely available through the internet.
In addition to the formal, quantitative approach to social network analysis, a qualitative approach to social networks is