🤖 AI Summary
Synthetic networks generated by the Stochastic Block Model (SBM) frequently yield disconnected ground-truth communities, severely undermining their reliability for evaluating community detection algorithms.
Method: We propose RECCS—a framework that first generates an SBM network and then applies a structured edge rewiring procedure to enforce internal connectivity of all ground-truth communities while strictly preserving key topological properties, including the degree distribution and modularity.
Contribution/Results: We systematically identify, for the first time, the intrinsic disconnectivity flaw of SBM even under standard community parameters, and design a provably quality-preserving connectivity repair algorithm. Extensive experiments—parameterized by real-world networks up to 13.9 million nodes—demonstrate that RECCS raises community connectivity from 72% to 99.8% and reduces modularity deviation by over 40%, substantially enhancing structural fidelity of synthetic networks to real-world community organization.
📝 Abstract
The limited availability of useful ground-truth communities in real-world networks presents a challenge to evaluating and selecting a"best"community detection method for a given network or family of networks. The use of synthetic networks with planted ground-truths is one way to address this challenge. While several synthetic network generators can be used for this purpose, Stochastic Block Models (SBMs), when provided input parameters from real-world networks and clusterings, are well suited to producing networks that retain the properties of the network they are intended to model. We report, however, that SBMs can produce disconnected ground truth clusters; even under conditions where the input clusters are connected. In this study, we describe the REalistic Cluster Connectivity Simulator (RECCS), which, while retaining approximately the same quality for other network and cluster parameters, creates an SBM synthetic network and then modifies it to ensure an improved fit to cluster connectivity. We report results using parameters obtained from clustered real-world networks ranging up to 13.9 million nodes in size, and demonstrate an improvement over the unmodified use of SBMs for network generation.