Invited Talks

Vincent Aleven Intelligent tutoring systems (ITS) are highly effective in supporting student learning, but are difficult to build. The Cognitive Tutor Authoring Tools (CTAT) project started over 6 years ago with the goals of making it easier for experienced programmers, and possible for non-programmers to create an ITS. CTAT supports tutor building through programming by demonstration, an approach that has been successful in a range of application areas, but that has been applied to only a very limited degree to ITS authoring. Using CTAT, an author creates a tutor by demonstrating correct and incorrect problem solving behaviors, rather than by writing code. The resulting tutors, called exampletracing tutors, evaluate student behavior by flexibly comparing it against the demonstrated problem-solving examples. A key question is whether programming-by-demonstration can support sophisticated tutor behavior. We illustrate that example-tracing tutors are capable of sophisticated tutoring behaviors, going well beyond VanLehn’s (2006) minimum criterion for ITS status. They provide step-by-step guidance on complex problems while recognizing multiple student strategies and maintaining multiple interpretations of student behavior when there is ambiguity. Example-tracing tutors have been built and used in real educational settings for a wide range of application areas. Development time estimates from these projects indicate that CTAT improves the cost-effectiveness of ITS development by a factor of 48, compared to historical estimates. Although there is a lot of variability in these kinds of estimates, they nevertheless support our hope that lowering the skill requirements for tutor creation will support widespread adoption of ITS technology. This talk reflects joint work with Bruce M. McLaren, Jonathan Sewall, Kenneth R. Koedinger, and the CTAT Team.