For many high school students, taking Advanced Placement or honors courses not only provides intellectual challenge, but a boost of the GPA. That's because many  high schools give bonus points in GPA's for such courses, so an A might count as a 5.0 rather than a 4.0.

In theory, these bonus points encourage students to take more challenging courses by removing any incentive they might have to keep a straight A average by taking easy classes. But a new report by the University of California suggests that these bonus points may not be quite as educationally sound as they appear.

Part of the problem identified by the report is equity. The gaps in AP and honors offerings among high schools are so wide that some students have the opportunity to consistently take honors courses, and others rarely get that chance. A broader problem is that not everyone who takes AP courses is really learning a lot.

"Merely taking AP or other honors level courses in high school is not a valid indicator of the likelihood that students will perform well in college," the report says. 

The problem is not that AP courses are bad, the report says, but that they were designed for college placement, not college admissions, as they are increasingly being used.