Title: Pitfalls of Graph Neural Network Evaluation,
Abstract: Semi-supervised node classification in graphs is a fundamental problem in
graph mining, and the recently proposed graph neural networks (GNNs) have
achieved unparalleled results on this task. Due to their massive success, GNNs
have attracted a lot of attention, and many novel architectures have been put
forward. In this paper we show that existing evaluation strategies for GNN
models have serious shortcomings. We show that using the same
train/validation/test splits of the same datasets, as well as making
significant changes to the training procedure (e.g. early stopping criteria)
precludes a fair comparison of different architectures. We perform a thorough
empirical evaluation of four prominent GNN models and show that considering
different splits of the data leads to dramatically different rankings of
models. Even more importantly, our findings suggest that simpler GNN
architectures are able to outperform the more sophisticated ones if the
hyperparameters and the training procedure are tuned fairly for all models.