Yes, magnet clusters have a concentration. A magnet cluster is a neighborhood school first (so takes all comers from their area) then open up remaining slots to kids citywide. There are a lot of them actually (http://cpsoae.org/apps/pages/index.j...pREC_ID=151365) so you may think about the area you want to live and target those first. Depending on the school, you may have a decent shot at getting middle-schoolers in. Newer programs are full at the bottom but not at the top and some can still have prinicpals entering kids at upper levels if there's no competition for those slots.