Table 2.

Social network parameters and their definitions

Term	Whole network or individual?	Definition
Node	Both	A node is a member of a network
Tie	Both	A tie represents a self-reported link between two nodes
Density	Whole network	The number of actual ties divided by the number of possible ties. Reported as a percentage
Reciprocity	Whole network	The extent to which ties between any two nodes is acknowledged by both. If there is full agreement across the network then reciprocity = 1.0; no agreement = 0.0
Clustering	Whole network	The extent to which nodes are grouped by an attribute
E-I Index	Whole network	External-internal index looks at actual ties versus expected ties relating to a certain attribute. It compares ties to members within that group (internal) to those outside (external) that group. Results are between −1.0 and +1.0 and have a p value
Degree	Both	Number of ties per node (either nominated by others or by the member themselves)
Indegree	Individuals	Number of ties reported by others directed to the focal member
Outdegree	Individuals	Number of ties reported by the focal member
Centrality	Individuals	Members with the highest interaction (ties to and from) with others
Betweenness centrality	Individuals	Members who have brokerage potential as they lie on the shortest path between two nodes that are not directly linked