When age-grouping ends up being closer to a 2 year span, these articles make me wonder why we do age-based grouping at all. It seems a much better argument for ability-based grouping.
There was a great blog post about this "tracking by age":
Ironically, the grade-level, whole-class groupings apparently preferred by these teachers who bemoan ability-grouping are the most restrictive form of tracking, that by age. For a century (-ish), schools have "tracked" students based on when they were born, not based on what they are ready and able to learn. "Born between September 1, 2003, and August 31, 2004? You belong to the Class of 2022." That is how it works in nearly every school in our country. It's tracking by age, but no one calls it that.
Let's start calling it that!
http://blogs.edweek.org/teachers/unwrapping_the_gifted/2010/07/abandoning_age-tracking.html
