1. A method for computing probabilistic measures for a labelled directed graph, said method comprising: accessing data representative of a labelled directed graph of nodes and labels connected by directed edges; determining, from the directed graph, a matrix of values representative of the influence between pairs of the nodes in the directed graph; and determining, from the matrix and a distribution of a particular label in the directed graph, one or more probabilistic measures associated with at least one of the nodes or labels of the directed graph.