Cognitive Tutor Authoring Tools 2.6 > CTAT Basics > Tutor TypesCTAT enables you to create two main types of tutors: Example-tracing Tutors, which can be created without programming, but require problem-specific authoring; and Cognitive Tutors, which require programming a cognitive model of student problem solving, but support tutoring across a range of similar problems.
There are a few factors that may influence your decision regarding which tutor type to build:
the complexity of the tutor problems (i.e., the problems that students solve as they work with the tutor);
whether many problems of the same type need to be developed;
how many alternative solutions paths exist for each problem;
whether subtle ordering constraints exist on the steps within the tutor problems;
whether later steps in a problem depend on earlier steps; and
whether in-house expertise in AI programming is available to develop a cognitive model.
If you are new to the process of creating a tutor, we recommend that you start with an Example-tracing Tutor.
For more information on the different types of tutors, see the Tutor Types page on the CTAT web site.
An Example-tracing Tutor is based on a single problem representation stored in a behavior graph (a BRD file, or behavior recorder data, file). You create this graph by demonstrating problem-solving steps with the student interface. (See Example-tracing Tutors for more on creating an Example-tracing Tutor.)
An Example-tracing Tutor works by comparing student actions to steps recorded in a graph. If the student action is represented in the graph as a correct action, the tutor marks the student action as correct; if the student action is represented in the graph as an incorrect action, or if the student action is not in the graph, the tutor marks the student action as incorrect. In addition to storing whether or not a student action is correct, the behavior graph stores a representation of step order, hint messages, error feedback messages, and other parameters. For more information on behavior graph (BRD) files, see Section 2, “Working with Behavior Graph (BRD) Files”.
By default, the following tools are shown when the Example-tracing Tutor type is selected:
Behavior Recorder
The Behavior Recorder is the only tool required to create an Example-tracing Tutor. In addition, you will need a student interface (built in Java or Flash) in which to demonstrate behavior.
To start creating an Example-tracing tutor, see Example-tracing Tutors, or try the CTAT tutorial on building an example-tracing tutor for the domain of fraction addition.