Exact ICL maximisation for the stochastic block transition model

Résumé

The latent stochastic block model is a flexible and widely used statistical model for the analysis of network data.
Extensions of this model to a dynamic context often fail to capture the persistence of edges in contiguous network snapshots.
The recently introduced stochastic block transition model addresses precisely this issue, by modelling the probabilities of creating a new edge and of maintaining an edge over time.
Using a model-based clustering approach, this paper illustrates a methodology to fit stochastic block transition models under a Bayesian framework.
The method relies on a greedy optimisation procedure to maximise the exact integrated completed likelihood.
The computational efficiency of the algorithm used makes the methodology scalable and appropriate for the analysis of large network datasets.
Crucially, the optimal number of latent groups is automatically selected at no additional computing cost.
The efficacy of the method is demonstrated through applications to both artificial and real datasets.