INSPIRE: A Framework for Integrating Individual User Preferences in Recourse

Most recourse generation approaches optimize for indirect distance-based metrics like diversity, proximity, and sparsity, or a shared cost function across all users to generate recourse. The latter is an unrealistic assumption because users can have diverse feature preferences which they might be willing to act upon and any changes to any undesirable feature might lead to an impractical recourse. In this work, we propose a novel framework to incorporate the individuality of users in both recourse generation and evaluation procedure by focusing on the cost incurred by a user when opting for a recourse. To achieve this, we first propose an objective function, Expected Minimum Cost (EMC) that is based on two key ideas: (1) the user should be comfortable adopting at least one solution when presented with multiple options, and (2) we can approximately optimize for users' satisfaction even when their true cost functions (i.e., costs associated with feature changes) are unknown. EMC samples multiple plausible cost functions based on diverse feature preferences in the population and then finds a recourse set with one good solution for each category of user preferences. We optimize EMC with a novel discrete optimization algorithm, Cost-Optimized Local Search (COLS), that is guaranteed to improve the quality of the recourse set over iterations. Our evaluation framework computes the fraction of satisfied users by simulating each user's cost function and then computing the incurred cost for the provided recourse set. Experimental evaluation on popular real-world datasets demonstrates that our method satisfies up to 25.9% more users compared to strong baselines. Moreover, the human evaluation shows that our recourses are preferred more than twice as often as the strongest baseline.