Degree centrality refers to the number of ties between group members. The group’s Degree centrality is the average of the direct connections among group members.
Degree centrality is a measure used in social network analysis to determine the importance of a node or an individual in a network by examining the number of connections or edges that a node has. The higher the degree centrality, the more connected the node is to other nodes in the network, and the more influence it can have in spreading information or affecting the behavior of others.
Degree centrality can be calculated using various methods, such as counting the number of direct connections (i.e., the number of other nodes with which the node shares an edge), or by using a weighted measure that takes into account the strength of the connections (i.e., the number of times the edge is used). Degree centrality can be applied to various types of networks, such as social networks, communication networks, or transportation networks.
Example:
Suppose we are interested in studying a social network of high school students. Each node in the network represents a student, and an edge represents a friendship relationship between two students. We can use degree centrality to identify the most popular or influential students in the network.
For instance, if student A has 10 friends, and student B has only 2 friends, student A would have a higher degree centrality than student B, as they are more connected to other individuals in the network. However, this does not necessarily mean that student A is the most influential student, as the strength of the connections or the quality of the relationships can vary.
Similar measures:

Betweenness centrality: measures the extent to which a node lies on the shortest path between other nodes in the network. Nodes with high betweenness centrality can act as brokers or gatekeepers, controlling the flow of information between different parts of the network.

Eigenvector centrality: measures the importance of a node based on the importance of its neighbors. Nodes with high eigenvector centrality are connected to other nodes that are themselves important, which gives them a higher influence in the network.

Closeness centrality: measures the average distance between a node and all other nodes in the network. Nodes with high closeness centrality are more likely to be reached quickly by other nodes in the network, and can therefore have a higher influence.
In summary, degree centrality is a useful measure in social network analysis for identifying the most connected or influential nodes in a network. However, it should be used in combination with other measures, such as betweenness centrality, eigenvector centrality, or closeness centrality, to obtain a more comprehensive picture of the network structure and the roles of different nodes.