I have a huge city, 99% of it is high density, I have only one university, two high schools and three grade schools and still somehow everyone is 'highly educated/unemployed'. so imagine my surprise when, after that residential zone developed, I checked its education status and all of its residents were friggin' sky blue. I haven't built any schools in that residential zone, and all the schools in my city centre were already packed to their full capacity. In order to build my slum I started creating a residential zone very far away from my city centre - so far it was actually on a different island. but I still have this problem, and there is one thing I really don't get about this.