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Table 1 Theoretical definition of social network analysis indicators presented herein and their meaning in this study

From: Dengue research networks: building evidence for policy and planning in Brazil

Indicator Definition Meaning in this study
Network size
Nodes Actors within a network Organisations in the co-authorship network
Links Relationships or connections between actors Co-authorship between organisations
Network connectivity/cohesion
Component Subset of nodes in a network in which all of them are linked to each other, directly or indirectly Group of organisations that were connected to one another through joint publications
Giant component Largest component existing in the network Largest group of organisations connected through joint publications; the larger the giant component size, or percentage of institutions included within it, the more interconnected the network is
Average degree Average number of direct connections the network nodes have Average number of collaborations per organisation; the higher the average degree, the more connected the network is
Average clustering coefficient Measures the extent to which the nodes in the network establish a perfect cluster, in which all the nodes are interconnected The extent of full connectivity between organisations; a high average clustering coefficient indicates that more institutions are interconnected within the network
Average path length Average smallest number of connections that a node needs in order to reach any other in the network The average distance between organisations; the lower the average path length, the more direct is the connection between organisations
Centrality/significance of nodes in the network
Degree centrality Number of a node’s direct connections A measure of how many direct contacts an organisation has Organisations with high degree centrality are usually focal points of communication in the network
Eigenvector centrality Reflects the quantity and quality of the direct connections a node has A measure of high connectivity and links to other highly connected organisations; higher values indicate influential organisations in the network
Betweeness centrality Indicates to what extent a node acts as a “bridge” between the various other nodes in the network, which would otherwise be disconnected A measure of how much an organisation mediates the connection between other institutions; an organisation with high betweeness centrality has the potential to control the flow of information in the network
Closeness centrality Measures how close a node is to all other nodes in the network A measure of the extent to which an organisation can directly reach others; organisations with high closeness centrality can quickly obtain and communicate information in the network