The Girvan–Newman algorithm (named after Michelle Girvan and Mark Newman) is a hierarchical method used to detect communities in complex systems.
[1] The Girvan–Newman algorithm detects communities by progressively removing edges from the original network.
By removing these edges, the groups are separated from one another and so the underlying community structure of the network is revealed.
The algorithm's steps for community detection are summarized below The fact that the only betweennesses being recalculated are only the ones which are affected by the removal, may lessen the running time of the process' simulation in computers.
As the Girvan–Newman algorithm runs, the dendrogram is produced from the top down (i.e. the network splits up into different communities with the successive removal of links).