We recently had an IEP meeting with a school principal who said school was "60% social skills and 40% academic" so I've been thinking about why schools are so invested in a particular notion of age-grade socialization. My tentative conclusion is that the stress on friends who are age mates has a lot to do with justifying school practices of keeping kids in lockstep throughout. Teachers and administrators know perfectly well that the range of abilities and the subject grade-level achievement in any particular class spans many years. Age organization is for administrative convenience, but if they admitted that it would undermine the whole system. The alternative is to insist that there's some intrinsic good that flows from socializing almost exclusively with people born in the same calendar year while occupying the same classroom space. Maybe we need to bring back one-room schoolhouses?