Do we use the Right Measure? Challenges in Evaluating Reward Learning Algorithms

Nils Wilde, Javier Alonso-Mora

Keywords: Human Robot Interaction, Reward Learning

TL;DR: We describe shortcomings in different measures used to evaluate reward learning algorithms in human robot interaction.

Abstract: Reward learning is a highly active area of research in human-robot interaction (HRI), allowing a broad range of users to specify complex robot behaviour. Experiments with simulated user input play a major role in the development and evaluation of reward learning algorithms due to the availability of a ground truth. In this paper, we review measures for evaluating reward learning algorithms used in HRI, most of which fall into two classes. In a theoretical worst case analysis and several examples, we show that both classes of measures can fail to effectively indicate how good the learned robot behaviour is. Thus, our work contributes to the characterization of sim-to-real gaps of reward learning in HRI.

Student First Author: no