Several years ago, I actually heard a presentation by the district math department espousing that students should NOT be accelerated more than one year. I seem to remember the justification being that the accelerated students didn't develop true "number sense" and tended to have math fall apart in college. He also said that they ran out of courses to take in high school. (?!)
At the same time, the district adopted the Investigations curriculum. The gt classes were allowed to accelerate the kids one full year. The district did not want any deviations from the curriculum so they could determine the effectiveness of the program. It was torture. Even with one year of acceleration, Investigations was/is painfully slow and repetitive, especially at the lower grades.
Mercifully, we've seen some movement away from the straight Investigations in the gt classes since last year. Teachers are allowed to pre-test at the beginning of the unit. If a student demonstrates mastery, then the teacher offers non-Investigations extensions on the same topic. Still, it varies somewhat from teacher to teacher. Overall, we've seen a significant improvement in pacing and content between DD12 and DD9's tenure.
