Collaborative fluency is the coordinated meshing of joint activities between members of a well-synchronized team. In this research project, we aim to build robotic agents that can work side-by-side humans by displaying the kind of fluency that humans are accustomed to from each other. In addition, despite increasing interest in collaborative fluency in the HRI community, we have been using ad-hoc, non-validated metrics to estimate the level of fluency provided by the robot, and experienced by the human collaborator. We will work to methodically define measures of collaborative fluency between a human and a robot.