Action Shapley: A Training Data Selection Metric for World Model in Reinforcement Learning
Rajat Ghosh, Debojyoti Dutta
TL;DR
This work introduces Action Shapley, an agnostic data-valuing metric designed to select high-impact training data for world-model training in model-based reinforcement learning. A randomized dynamic algorithm enables scalable approximation of data-point Shapley values, balancing accuracy with computational efficiency. Across five real-world, data-constrained case studies, Action Shapley identifies indispensable data points and guides a data-selection policy that outperforms ad-hoc choices, achieving substantial computational savings (up to and exceeding 80% over exhaustive Shapley computations) while maintaining or improving cumulative reward performance. The approach is compatible with various world-model and RL algorithms, and its principled data-selection framework promises improved data efficiency and robustness for real-world dynamic control applications.
Abstract
Numerous offline and model-based reinforcement learning systems incorporate world models to emulate the inherent environments. A world model is particularly important in scenarios where direct interactions with the real environment is costly, dangerous, or impractical. The efficacy and interpretability of such world models are notably contingent upon the quality of the underlying training data. In this context, we introduce Action Shapley as an agnostic metric for the judicious and unbiased selection of training data. To facilitate the computation of Action Shapley, we present a randomized dynamic algorithm specifically designed to mitigate the exponential complexity inherent in traditional Shapley value computations. Through empirical validation across five data-constrained real-world case studies, the algorithm demonstrates a computational efficiency improvement exceeding 80\% in comparison to conventional exponential time computations. Furthermore, our Action Shapley-based training data selection policy consistently outperforms ad-hoc training data selection.
