Authoring Problem-Solving ITS with ASTUS

Step-based ITS have been proven successful for well-defined domains, particularly in well-defined tasks, but their success is mitigated by their cost Typically, the main factor behind the cost is the efforts needed to model the task domain Different approaches have been investigated to reduce these efforts: Model-Tracing Tutors (e.g Cognitive Tutors, Andes), Constraint-Based Tutors (e.g SQL-Tutor, ASPIRE) and Example-Tracing Tutors (e.g CTAT's, ASSISTment).