Graph Neural Networks for Source Detection: A Review and Benchmark Study

TL;DR

This paper reviews and benchmarks GNN-based methods for epidemic source detection, demonstrating their superior performance over traditional approaches across various network types and advocating for this task as a GNN evaluation benchmark.

Contribution

It provides a comprehensive review, proposes a tailored GNN architecture, and systematically compares GNNs with traditional methods, establishing their effectiveness for source detection.

Findings

GNNs outperform traditional methods in source detection accuracy

The proposed GNN architecture improves detection performance

Source detection is recommended as a benchmark for GNN evaluation

Abstract

The source detection problem arises when an epidemic process unfolds over a contact network, and the objective is to identify its point of origin, i.e., the source node. Research on this problem began with the seminal work of Shah and Zaman in 2010, who formally defined it and introduced the notion of rumor centrality. With the emergence of Graph Neural Networks (GNNs), several studies have proposed GNN-based approaches to source detection. However, some of these works lack methodological clarity and/or are hard to reproduce. As a result, it remains unclear (to us, at least) whether GNNs truly outperform more traditional source detection methods across comparable settings. In this paper, we first review existing GNN-based methods for source detection, clearly outlining the specific settings each addresses and the models they employ. Building on this research, we propose a principled GNN architecture tailored to the source detection task. We also systematically investigate key questions surrounding this problem. Most importantly, we aim to provide a definitive assessment of how GNNs perform relative to other source detection methods. Our experiments show that GNNs substantially outperform all other methods we test across a variety of network types. Although we initially set out to challenge the notion of GNNs as a solution to source detection, our results instead demonstrate their remarkable effectiveness for this task. We discuss possible reasons for this strong performance. To ensure full reproducibility, we release all code and data on GitHub. Finally, we argue that epidemic source detection should serve as a benchmark task for evaluating GNN architectures.