Assessment is a key component of the learning process. In order to maximize student learning, instructors need to provide students with appropriate, explicit and timely assessment. Despite the potential benefits of problem-based learning, some instructors may be reluctant to adopt this approach because it will require them to modify their current assessment practices. In problem-based learning curricula, assessment should be used to encourage and reward student participation throughout the course. This paper presents an analytical rubric developed for diagnosis of student learning via formative assessment in a capstone environmental impact analysis course. The use and role of the analytical rubric in student grading is also explained. This rubric provides a template for how student learning could be assessed in other courses in geography curricula that employ a similar student-centred approach to learning. (Contains 5 tables.)