 Critics say that not challenging all students with the most advanced curriculum results in overall low student educational achievement, and that students in low tracks do not learn as much as their peers in higher tracks, e.g., advanced mathematics.Teachers typically have higher expectations for students in high-track classes and low expectations for students in low-tracked classes, which affects the self-image of students.Detracking has been proven to reduce the achievement of students who would otherwise be placed in high-track classes.