The development and implementation of varied assessment practices is a major focus in higher education. Assessment benefits both students and teachers; it informs teachers about students' learning and misconceptions, thereby helping teachers improve teaching practices and students assess their current state of understanding. In general, the field lacks a rubric or an assessment model for assessing students' understanding of science content and their representations, which was the impetus for this study. The rubric developed in this study will help instructors assess students' representational competence in a course-based research experience (CURE) and could also be adapted to assess students' understanding of other scientific concepts and misconceptions. The rubric will enable teachers to collect evidence of students' understanding so they can make their science teaching more authentic, support students' learning of the core scientific concepts, and provide an opportunity for teachers to modify their instruction accordingly across science disciplines, benefitting science teaching and learning overall.