Interpretability of Deep Learning (DL) is a barrier to trustworthy AI.
Despite great efforts made by the Explainable AI (XAI) community, explanations
lack robustness -- indistinguishable input perturbations may lead to different
XAI results. Thus, it is vital to assess how robust DL interpretability is,
given an XAI method. In this paper, we identify several challenges that the
state-of-the-art is unable to cope with collectively: i) existing metrics are
not comprehensive; ii) XAI techniques are highly heterogeneous; iii)
misinterpretations are normally rare events. To tackle these challenges, we
introduce two black-box evaluation methods, concerning the worst-case
interpretation discrepancy and a probabilistic notion of how robust in general,
respectively. Genetic Algorithm (GA) with bespoke fitness function is used to
solve constrained optimisation for efficient worst-case evaluation. Subset
Simulation (SS), dedicated to estimate rare event probabilities, is used for
evaluating overall robustness. Experiments show that the accuracy, sensitivity,
and efficiency of our methods outperform the state-of-the-arts. Finally, we
demonstrate two applications of our methods: ranking robust XAI methods and
selecting training schemes to improve both classification and interpretation
robustness.Comment: Accepted by the IEEE/CVF International Conference on Computer Vision
2023 (ICCV'23