What do you think of student tracking?

Many public schools assign students to different academic "tracks" based on ability. What's wrong with tracking? Do schools start too early or stick to a student's assigned place too stubbornly? What's right with tracking? How else would we efficiently teach students with different abilities? How does tracking help and harm students? Are you a teacher or parent willing to comment on the pros and/or cons of tracking students? If so, please contact reporter Lisa Kocian at 508-820-4231 or lkocian@globe.com.