Title: Interpreting Deep Neural Networks Through Variable Importance,
Abstract: While the success of deep neural networks (DNNs) is well-established across a
variety of domains, our ability to explain and interpret these methods is
limited. Unlike previously proposed local methods which try to explain
particular classification decisions, we focus on global interpretability and
ask a universally applicable question: given a trained model, which features
are the most important? In the context of neural networks, a feature is rarely
important on its own, so our strategy is specifically designed to leverage
partial covariance structures and incorporate variable dependence into feature
ranking. Our methodological contributions in this paper are two-fold. First, we
propose an effect size analogue for DNNs that is appropriate for applications
with highly collinear predictors (ubiquitous in computer vision). Second, we
extend the recently proposed "RelATive cEntrality" (RATE) measure (Crawford et
al., 2019) to the Bayesian deep learning setting. RATE applies an information
theoretic criterion to the posterior distribution of effect sizes to assess
feature significance. We apply our framework to three broad application areas:
computer vision, natural language processing, and social science.