At the turn of the last century, Alfred Binet wanted to identify those students who needed special help in school. This idea has been horribly misused time and time again.
Educators and anyone with more then one kid, knows that there are different learning styles.
Dr. Kolb identified and categorized four of them. (this was probably a mistake, oh well)
Converging - the decision maker (active experimentation-abstract conceptualization) Accommodating - the do-er (active experimentation-concrete experience)
Assimilating - the planner (reflective observation-abstract conceptualization)
Diverging - the creator (reflective observation-concrete experience)
From the two above idea's, wouldn't you want to group children by ability and learning style to most effectively teach kids?
The current method of age grouping may have some kind of advantage, I just am not sure I can figure out what that would be.
I have two kids... geeze, One Adult and one young adult, who went through the public education system, did very well and came out with enough tools to deal with life. My youngest is unique in ability and learning style and trying to find teachers with the skills and understanding is a challenge.
I have found quite a few educators have sever limits they cannot overcome when dealing with children outside of a certain behavior variable. These teachers and their peers seem unaware of said limits until the teacher is put into the situation. Then getting the feedback that makes enough sense to change, or alter the situation is VERY difficult.
You heard that Cops have a code of silence? Teachers turn a blind eye to there comrades abilities and lack there of a lot.