Can I Still Trust You?: Understanding the Impact of Distribution Shifts on Algorithmic Recourses

As predictive models are being increasingly deployed to make a variety of consequential decisions ranging from hiring decisions to loan approvals, there is growing emphasis on designing algorithms that can provide reliable recourses to affected individuals. In this work, we assess the reliability of algorithmic recourses through the lens of distribution shifts i.e., we study if the recourses generated by state-of-the-art algorithms are robust to distribution shifts. To the best of our knowledge, this work makes the first attempt at addressing this critical question. We experiment with multiple synthetic and real world datasets capturing different kinds of distribution shifts including temporal shifts, geospatial shifts, and shifts due to data corrections. Our results demonstrate that all the aforementioned distribution shifts could potentially invalidate the recourses generated by state-of-the-art algorithms. Our theoretical results establish a lower bound on the probability of recourse invalidation due to distribution shifts, and show the existence of a tradeoff between this invalidation probability and typical notions of cost minimized by modern recourse generation algorithms. Our findings not only expose fundamental flaws in recourse finding strategies but also pave new way for rethinking the design and development of recourse generation algorithms.