This is the third annual, full-day workshop that aims to explore the state-of-practice in the metrology necessary for repeatably and independently assessing the performance of robotic systems in realworld human-robot interaction (HRI) scenarios. This workshop continues the aims of shortening the lead time between between the theory and applications of HRI, enabling reproducible studies, and accelerating the adoption of cutting edge technologies as the industry state-of-practice. This third installment of the annual workshop, "Test Methods and Metrics for Effective HRI,' seeks to identify novel and emerging test methods and metrics for the holistic assessment and assurance of HRI performance. The focus is on identifying innovative metrics and test methods for the evaluation of HRI performance, and to advance the growth of the HRI community based on the principles of collaboration, data sharing, and repeatability. The goal of this workshop is to aid in the advancement of HRI technologies through the development of experimental design, test methods, and metrics for assessing interaction and interface designs.