Network compression with configuration models and the minimum description length

TL;DR

This paper evaluates different network models using the minimum description length principle, finding that the classic configuration model suits dense networks while layered models better compress sparse networks.

Contribution

It introduces a method to compare network models based on information content and applies it to select optimal models for various network types.

Findings

Classic configuration model preferred for networks with degree > 10

Layered configuration model best for sparse networks

Model selection based on minimum description length

Abstract

Random network models, constrained to reproduce specific statistical features, are often used to represent and analyze network data and their mathematical descriptions. Chief among them, the configuration model constrains random networks by their degree distribution and is foundational to many areas of network science. However, configuration models and their variants are often selected based on intuition or mathematical and computational simplicity rather than on statistical evidence. To evaluate the quality of a network representation, we need to consider both the amount of information required to specify a random network model and the probability of recovering the original data when using the model as a generative process. To this end, we calculate the approximate size of network ensembles generated by the popular configuration model and its generalizations, including versions accounting for degree correlations and centrality layers. We then apply the minimum description length principle as a model selection criterion over the resulting nested family of configuration models. Using a dataset of over 100 networks from various domains, we find that the classic Configuration Model is generally preferred on networks with an average degree above ten, while a Layered Configuration Model constrained by a centrality metric offers the most compact representation of the majority of sparse networks.