Trajectory Inspection: A Method for Iterative Clinician-Driven Design of Reinforcement Learning Studies
This addresses the challenge of making RL policies more reliable and trustworthy for clinical deployment, though it is incremental as it builds on existing RL methods.
The paper tackles the problem of reinforcement learning (RL) models for clinical decision-making being sensitive to design choices by proposing trajectory inspection, a method that involves clinicians in iterative design to identify issues like model biases and implausible recommendations, as demonstrated in a sepsis management case study.
Reinforcement learning (RL) has the potential to significantly improve clinical decision making. However, treatment policies learned via RL from observational data are sensitive to subtle choices in study design. We highlight a simple approach, trajectory inspection, to bring clinicians into an iterative design process for model-based RL studies. We identify where the model recommends unexpectedly aggressive treatments or expects surprisingly positive outcomes from its recommendations. Then, we examine clinical trajectories simulated with the learned model and policy alongside the actual hospital course. Applying this approach to recent work on RL for sepsis management, we uncover a model bias towards discharge, a preference for high vasopressor doses that may be linked to small sample sizes, and clinically implausible expectations of discharge without weaning off vasopressors. We hope that iterations of detecting and addressing the issues unearthed by our method will result in RL policies that inspire more confidence in deployment.