Machine Unlearning for Causal Inference

Machine learning models play a vital role in making predictions and deriving insights from data and are being increasingly used for causal inference. To preserve user privacy, it is important to enable the model to forget some of its learning/captured information about a given user (machine unlearning). This paper introduces the concept of machine unlearning for causal inference, particularly propensity score matching and treatment effect estimation, which aims to refine and improve the performance of machine learning models for causal analysis given the above unlearning requirements. The paper presents a methodology for machine unlearning using a neural network-based propensity score model. The dataset used in the study is the Lalonde dataset, a widely used dataset for evaluating the effectiveness i.e. the treatment effect of job training programs. The methodology involves training an initial propensity score model on the original dataset and then creating forget sets by selectively removing instances, as well as matched instance pairs. based on propensity score matching. These forget sets are used to evaluate the retrained model, allowing for the elimination of unwanted associations. The actual retraining of the model is performed using the retain set. The experimental results demonstrate the effectiveness of the machine unlearning approach. The distribution and histogram analysis of propensity scores before and after unlearning provide insights into the impact of the unlearning process on the data. This study represents the first attempt to apply machine unlearning techniques to causal inference.