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Bayesian Counterfactual Risk Minimization
Proceedings of the 36th International Conference on Machine Learning, PMLR 97:4125-4133, 2019.
Abstract
We present a Bayesian view of counterfactual risk minimization (CRM) for offline learning from logged bandit feedback. Using PAC-Bayesian analysis, we derive a new generalization bound for the truncated inverse propensity score estimator. We apply the bound to a class of Bayesian policies, which motivates a novel, potentially data-dependent, regularization technique for CRM. Experimental results indicate that this technique outperforms standard L2 regularization, and that it is competitive with variance regularization while being both simpler to implement and more computationally efficient.