About social network analysis
A social network consists of a set of individuals and the relationships between them. Social network analysis examines these relationships to describe individuals and groups as parts of a social structure. Individuals interact with each other and these interaction patterns provide insight into the individuals involved. Relationships enable information to flow across a network, enabling one individual to influence another. The importance of the relationship information sets social network analysis apart from other approaches. Instead of focusing on each individual separately, the unit of study is a dyad consisting of two individuals and their relationships.
Relationships in a network can be classified as either directional or nondirectional. In a directional relationship, one individual is identified as the initiator, or source, of the relationship and the other is identified as the receiver, or destination. For example, making a phone call is a directional relationship in which one person calls another. In contrast, the roles of source and destination cannot be defined for nondirectional relationships. In this case, both parties participate in the relationship equally. Speaking to each other is an example of a nondirectional relationship.
Another property that distinguishes between relationships is whether the relationship is dichotomous or valued. The only information available in a dichotomous relationship is whether or not the relationship exists between two individuals. For every dyad in the network, the relationship is either present or absent. A valued relationship, on the other hand, includes a weight indicating the strength of the relationship. The weights allow the relationships to be compared to each other.
The "Relationship types" table lists examples for the cross-classification of relationships by direction and scale. In the directional relationships, Joe is the source of the relationship and Mary is the destination. In the nondirectional relationships, there is no indication of who initiated the relationship. The valued relationships use the length of the conversation as the relationship weight, while the dichotomous relationships either occurred or they did not.
| Direction | Scale | Example |
|---|---|---|
| Nondirectional | Dichotomous | Joe and Mary spoke to each other |
| Nondirectional | Valued | Joe and Mary spoke to each other for 20 minutes |
| Directional | Dichotomous | Joe called Mary |
| Directional | Valued | Joe called Mary for a 20 minute conversation |
For more information about the field of social network analysis, consult one of the comprehensive books in this area 1.