  Offline reinforcement learning (RL), also known as batch RL, offers the
prospect of policy optimization from large pre-recorded datasets without online
environment interaction. It addresses challenges with regard to the cost of
data collection and safety, both of which are particularly pertinent to
real-world applications of RL. Unfortunately, most off-policy algorithms
perform poorly when learning from a fixed dataset. In this paper, we propose a
novel offline RL algorithm to learn policies from data using a form of
critic-regularized regression (CRR). We find that CRR performs surprisingly
well and scales to tasks with high-dimensional state and action spaces --
outperforming several state-of-the-art offline RL algorithms by a significant
margin on a wide range of benchmark tasks.
