Unpacking the Black Box: Regulating Algorithmic Decisions

We show how to optimally regulate prediction algorithms in a world where an agent uses complex 'black-box' prediction functions to make decisions such as lending, medical testing, or hiring, and where a principal is limited in how much she can learn about the agent's black-box model. We show that limiting agents to prediction functions that are simple enough to be fully transparent is inefficient as long as the misalignment is limited and first-best prediction functions are sufficiently complex. Algorithmic audits can improve welfare, but the gains depend on the design of the audit tools. Tools that focus on minimizing overall information loss, the focus of many explainer tools, will generally be inefficient since they focus on explaining the average behavior of the prediction function. Targeted tools that focus on the source of incentive misalignment, e.g., excess false positives or racial disparities, can provide second-best solutions. We provide empirical support for our theoretical findings using an application in consumer lending, where we document that complex models regulated based on context-specific explanation tools outperform simple, fully transparent models. This gain from complex models represents a Pareto improvement across our empirical applications that are preferred both by the lender and from the perspective of the financial regulator.