> I also liked that they had children of various years in the same classroom. I think it promoted knowledge sharing from the older kids to the younger ones, and it removed barriers for friendships. Some of my best friends back then where older than I was. That would never happen in middle or high school.

In my own experience multi-year/grade classrooms seemed more fun and interesting, and I think there were social and educational benefits as well.

My perception is that in the US multi-year tends to be largely limited to elective courses, clubs, sports, and extracurricular activities.

(Unfortunately a typical "college preparatory" track in secondary school can interfere with elective courses such as arts courses or practical courses, both of which seem to be viewed as less important by many schools and college admissions departments. I wonder whether California proposition 28 will expand access to arts courses and activities?)