Which corporation makes the "canned" courses?
And what do you mean by "homemade" courses?
AP History was created by a subsidiary of McMillan called Bedford St. Martin's. CTY was also looking at in-licensing a number of courses from an online education company. can't remember its name now. The courses were made for at-risk students, not gifted students. This is the problem with an in-licensed course: it isn't made with gifted kids in mind and therefore may not meet their needs.
The homemade courses tend to be made specifically for CTY. Crafting the Essay is an example of one of these courses.
