Accurate and Scalable Estimation of Epistemic Uncertainty for Graph Neural Networks

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Hauptverfasser: Trivedi, Puja, Heimann, Mark, Anirudh, Rushil, Koutra, Danai, Thiagarajan, Jayaraman J.
Format: Preprint
Veröffentlicht: 2024
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author Trivedi, Puja
Heimann, Mark
Anirudh, Rushil
Koutra, Danai
Thiagarajan, Jayaraman J.
author_facet Trivedi, Puja
Heimann, Mark
Anirudh, Rushil
Koutra, Danai
Thiagarajan, Jayaraman J.
contents While graph neural networks (GNNs) are widely used for node and graph representation learning tasks, the reliability of GNN uncertainty estimates under distribution shifts remains relatively under-explored. Indeed, while post-hoc calibration strategies can be used to improve in-distribution calibration, they need not also improve calibration under distribution shift. However, techniques which produce GNNs with better intrinsic uncertainty estimates are particularly valuable, as they can always be combined with post-hoc strategies later. Therefore, in this work, we propose G-$Δ$UQ, a novel training framework designed to improve intrinsic GNN uncertainty estimates. Our framework adapts the principle of stochastic data centering to graph data through novel graph anchoring strategies, and is able to support partially stochastic GNNs. While, the prevalent wisdom is that fully stochastic networks are necessary to obtain reliable estimates, we find that the functional diversity induced by our anchoring strategies when sampling hypotheses renders this unnecessary and allows us to support G-$Δ$UQ on pretrained models. Indeed, through extensive evaluation under covariate, concept and graph size shifts, we show that G-$Δ$UQ leads to better calibrated GNNs for node and graph classification. Further, it also improves performance on the uncertainty-based tasks of out-of-distribution detection and generalization gap estimation. Overall, our work provides insights into uncertainty estimation for GNNs, and demonstrates the utility of G-$Δ$UQ in obtaining reliable estimates.
format Preprint
id arxiv_https___arxiv_org_abs_2401_03350
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Accurate and Scalable Estimation of Epistemic Uncertainty for Graph Neural Networks
Trivedi, Puja
Heimann, Mark
Anirudh, Rushil
Koutra, Danai
Thiagarajan, Jayaraman J.
Machine Learning
While graph neural networks (GNNs) are widely used for node and graph representation learning tasks, the reliability of GNN uncertainty estimates under distribution shifts remains relatively under-explored. Indeed, while post-hoc calibration strategies can be used to improve in-distribution calibration, they need not also improve calibration under distribution shift. However, techniques which produce GNNs with better intrinsic uncertainty estimates are particularly valuable, as they can always be combined with post-hoc strategies later. Therefore, in this work, we propose G-$Δ$UQ, a novel training framework designed to improve intrinsic GNN uncertainty estimates. Our framework adapts the principle of stochastic data centering to graph data through novel graph anchoring strategies, and is able to support partially stochastic GNNs. While, the prevalent wisdom is that fully stochastic networks are necessary to obtain reliable estimates, we find that the functional diversity induced by our anchoring strategies when sampling hypotheses renders this unnecessary and allows us to support G-$Δ$UQ on pretrained models. Indeed, through extensive evaluation under covariate, concept and graph size shifts, we show that G-$Δ$UQ leads to better calibrated GNNs for node and graph classification. Further, it also improves performance on the uncertainty-based tasks of out-of-distribution detection and generalization gap estimation. Overall, our work provides insights into uncertainty estimation for GNNs, and demonstrates the utility of G-$Δ$UQ in obtaining reliable estimates.
title Accurate and Scalable Estimation of Epistemic Uncertainty for Graph Neural Networks
topic Machine Learning
url https://arxiv.org/abs/2401.03350