Closeness is a radial measure of centrality that favors actors who are connected with many others via short paths.
The raw closeness score of a node is defined as the reciprocal of its total distance to those it can reach via directed paths,
where denotes the length of a shortest directed path from to . If a link strength has been selected, the length of an -path is the sum of the corresponding attribute values of all links in the path.
Definition (simple case)
On directed, unweighted graphs that are strongly connected, the closeness centrality of a node is defined as
where denotes the length of a shortest directed path from to .