a computer-based system whose primary task is to help learners identify their knowledge, difficulties and misconceptions in a subject in order that they can focus their efforts where most required through formative assessment. The system dynamically infers and constructs a model of students’ understanding as they answer questions and is continually updated as they interact further. Students can view this individual ‘learner model’ which offers simple representations of their knowledge state. They can also compare their knowledge level with that of their peer group and with instructor/lecturer expectations for the current stage of the course. Instructors can set up their own questions to ensure that the environment is suitable for their specific courses.