Much research has been done on open student models within adaptive educational systems. It has been shown that opening up the student model, and allowing the student to view their model is useful in the learning process. Open student models help support meta-cognitive process, such as self-reflection. Negotiable student models take this a step further, and allow students to negotiate and potentially modify their model. A few negotiable student models have been implemented, but only in relatively simple systems, and not integrated into a complex ITS. As such, it is not clearly known if negotiable student models pose a significant advantage over the traditional open student models. This research implements a basic negotiable student model into a version of a complex and internationally deployed ITS. Subjective evaluation is performed, and shows promising results. Participants felt the negotiable student model was both useful for learning, and enjoyable to use. With a few improvements, this negotiable student model implementation could be used in a wide-scale objective analysis to help determine the usefulness of negotiable student models.