Learning through Recourse under Censoring

Machine learning models are often deployed in dynamic systems that involve data collection and model updates. In consumer finance, for example, lenders deploy a model to automate lending decisions, collect data from applicants, and then use it to update the model for future applicants. In such systems, data collection suffers from \emph{selective labeling}, as we only observe outcomes for applicants who are approved. When these systems are initialized with models deny loans to a specific group, they exhibit \emph{censoring} whereby they deny loans to a group of consumers in perpetuity.In this work, we identify conditions when machine learning systems exhibit censoring. We study the ability to resolve censoring by providing \emph{recourse} -- i.e., by providing applicants who are denied with actions that guarantee approval. We develop a method to learn linear classifiers with recourse guarantees, which allows model owners to update their models while providing prior applicants with a guarantee of approval. We benchmark our method and other strategies for exploration in their ability to resolve censoring. Our results illustrate the costs of each strategy on key stakeholders, provide insight into failure modes that lead to censoring, and highlight the importance of the feasibility of recourse.