I think it is easier to compact before Algebra I. If not, even MG kids willl be bored stiff in elementary years. The new common core dig deeper in Algebra 1, Geometry, etc.. and I may not want to compact those. I would compact prealgebra and start Algebra I at 7th grade for Gifted kids. Perhaps, a few PG kids may join that class in 6th grade. Besides, there aren't enough students (typical school district) who can handle Algebra I, II and Geometry in 2 years in a typical school setting (with lots of homework).
School District and formal documentation from the state discourage compacting before 6/7th grade. I know.. I don't necessarily agree with this. And while I agree with you that compacting that goes into elementary would be useful, it's not really on the table. I have heard (through this board) that other schools are compacting 7/8/9th for junior high. This takes you through pre-algebra, grade 8, and algebra I class. This includes a few chapters of geometry and some of what used to be algebra II by the end of 8th. Instead of the old system where these kids did Algebra I & Geometry by 8th grade. I think most kids who are gifted in math can handle this. Many of the kids in the honors elementary program will probably already see some pre-algebra anyway.
Another huge issue on the table is allowing "track" movement, ie.. a way for those kids who didn't hit whatever cutoff at 12/13 but took off once they are older (they do exist) to have a chance to get into the highest level math courses including Calculus before graduating. This is big because in order to keep these compacted classes down to just those kids who really are ready to handle it, another alternative towards Calculus before college needs to be available. The new Common Core standards taking they way they are designed doesn't get kids to Calculus and for most average kids that is OK.. it's really only important to those wanting to go into STEM & maybe bushiness in College.
As to numbers of kids, our district HAS those numbers of kids. (Our H.S. wins national math competitions partly because of the number of gifted math kids.) There were 90+ kid taking Geometry in 8th grade at my son's junior high (big junior high), and there were two 7th graders in that class. We do have a large number of kids who's parents at least WANT them to do this. Not sure if it's good for all of them. The more kid who are pushed to do this causes a backlash from the teachers because they get frustrated trying to teach kids who aren't really ready.
