I'm not familiar with tracking. Does this mean: one set of kids are on track to do well and the others are on track to not do as well? Is the position that the grouping would keep kids in a lower group from acheiving as well because they are labeled "less potential or inferior"?
No, it means that the students are taught at their ability level. One of my neighbors has a son at the lowest track and she is very pleased that he is being taught at the right pace for him.
I volunteer at the school with kids at the low end in third grade. Those kids need extra time, more repetition to learn. The school is not holding them back. On the contrary, they're being offered the right resources to help them succeed. I'm tutoring one girl who is learning English. When her scores improve, she will be moved up.