Non-AP high school economics would not normally be a heavyweight course. Indeed, an English elective may be considered a more rigorous course by an outside observer.
Which one is actually more rigorous may depend on the school. He may want to find out what kind of students take these courses. I.e. are these courses normally populated by the A students in the school, or by the students who are barely passing and content with D grades needed to pass the course to earn credit for high school graduation?