Tracking programs place students in classes based on what are perceived to be their intellectual abilities. For example, a student who scores high on a standardized test may be placed in more challenging classes than a student who scores low on the same test. If students score high in math, but not in English, they may be placed in more challenging math classes, but in less challenging English classes. Schools and school districts determine class levels and the grouping of students. Students who demonstrate high ability may be placed in “honors” or “gifted” classes. Students in these classes sometimes receive extra grade points for the added challenge. Students who have performed well in high school classes may be eligible to take Advanced Placement (AP) classes. These classes are modeled after college classes and require more work than typical high school classes. Students can take a variety of AP classes including world history, English, chemistry, biology, and algebra. Students can earn college credit for successfully completing an AP course. Tracking is a controversial educational practice throughout America. Supporters of tracking systems believe that students learn best when learning with peers who share similar abilities. Opponents, however, believe that students in the lower level classes miss out on challenging activities and skills that are offered in the advanced classes.