Causal Effect Regularization: Automated Detection and Removal of Spurious Correlations

In many classification datasets, the task labels are spuriously correlated with some input attributes. Classifiers trained on such datasets often rely on these attributes for prediction, especially when the spurious correlation is high, and thus fail togeneralize whenever there is a shift in the attributes’ correlation at deployment. If we assume that the spurious attributes are known a priori, several methods have been proposed to learn a classifier that is invariant to the specified attributes. However, in real-world data, information about spurious attributes is typically unavailable. Therefore, we propose a method that automatically identifies spurious attributes by estimating their causal effect on the label and then uses a regularization objective to mitigate the classifier’s reliance on them. Although causal effect of an attribute on the label is not always identified, we present two commonly occurring data-generating processes where the effect can be identified. Compared to recent work for identifying spurious attributes, we find that our method, AutoACER, ismore accurate in removing the attribute from the learned model, especially when spurious correlation is high. Specifically, across synthetic, semi-synthetic, and real-world datasets, AutoACER shows significant improvement in a metric used to quantify the dependence of a classifier on spurious attributes ($\Delta$Prob), while obtaining better or similar accuracy. Empirically we find that AutoACER mitigatesthe reliance on spurious attributes even under noisy estimation of causal effects or when the causal effect is not identified. To explain the empirical robustness of our method, we create a simple linear classification task with two sets of attributes: causal and spurious. Under this setting, we prove that AutoACER only requires the ranking of estimated causal effects to be correct across attributes to select thecorrect classifier.