(AP)—When it comes to high school math, the course titles don't really matter or even predict what's in the textbook.

That observation is part of the 's new study of high school math courses released Tuesday. During its review of almost 18,000 ' records and textbooks, the investigators found as much as a third of the textbooks weren't about the subject printed on the cover. And within the subjects, the course titles were subjective and didn't really reflect the courses' difficulty.

Some experts worry that this could foretell a situation similar to grade inflation. Linda Rosen, a former math teacher who leads business leaders' efforts to boost science and , says the nation could now face what she calls "course-title inflation."