Intelligent tutor system (ITS) was started by Kurt VanLehn in 2006 Each ITS system consists of 1) Task domain 2) Task - a multi minute activity that can be skipped or interchanged with other tasks. 3) Step - completing many tasks at once Terminology: 1) Knowledge Component - a task domain concept principle, fact, etc. Any fragment of the persistent domain specific information that should be used to accomplish tasks. 2) Learning Event: - A mental event and the construction or application of a knowledge component often while trying to achieve a task. 3) Incorrect: Inconsistent with the instructional objectives of the tutor.