🤖 AI Summary
This work addresses the lack of a systematic classification for missing data mechanisms in attributed graphs, where conventional methods fail to capture the joint influence of graph structure and node attributes on missingness patterns. To this end, we propose the Graph-Aware Missingness Mechanism (GAMM) framework, which establishes the first missing data taxonomy tailored to attributed graphs by modeling missingness probabilities as a function of both node attributes and graph topology, thereby relaxing the i.i.d. assumption. Through comprehensive evaluation involving probabilistic modeling, graph neural networks, and imputation algorithms, our experiments demonstrate that state-of-the-art imputation methods suffer significant performance degradation under GAMM-defined graph-aware missingness scenarios, underscoring the practical relevance and challenge of the proposed classification framework.
📝 Abstract
Exploring missing data in attributed graphs introduces unique challenges beyond those found in tabular datasets. In this work, we extend the taxonomy for missing data mechanisms to attributed graphs by proposing GAMM (Graph Attributes Missing Mechanisms), a framework that systematically links missingness probability to both node attributes and the underlying graph structure. Our taxonomy enriches the conventional definitions of masking mechanisms by introducing graph-specific dependencies. We empirically demonstrate that state-of-the-art imputation methods, while effective on traditional masks, significantly struggle when confronted with these more realistic graph-aware missingness scenarios.