This article focuses on the validity of the new Narrative Reflection Assessment Rubric (NARRA) used to assess students' reflective narratives in higher education. We evaluate its formulation and usefulness from an instructional point of view. To those ends, we engage in both a quantitative and a qualitative analysis, using data from 100+ preservice teachers before and after they attend a Reflective Practice Seminar. We find that there are statistically significant differences in student scores between the pre-seminar test and the post-seminar test, suggesting both that students learned to reflect in the framework of the seminar and that the rubric is a valid and reliable instrument to measure this learning. We also establish five categories about the usefulness of the rubric: description, intrapersonal inquiry, interpersonal inquiry, argumentation and improvement. We conclude that the NARRA is a useful tool for identifying students' current level of reflection in higher education.