We demonstrate the power planning techniques can have for the task of analyzing planning solutions in a classroom setting. Using the common assignment strategy of asking students to develop PDDL given an English description of a domain, we consider how a variety of planning methods (existing and new) can provide analytic support for teaching staff to understand which errors were made in student models. The work has already had a direct and practical impact, being deployed in a classroom setting to assess the correctness of student-authored planning models.