I taught in an inner city title one school. While it would have made teaching those who showed up easier, I'd bet that over half the students would not show up without forced attendance. We had under 2% of students who would go on to graduate a four year college and something like an 80% transitory rate (meaning 20% would complete all four years at the school - this might have been up to 95% transitory, it has been a while since I was there). Gangs, violence, and poverty and no examples of school helping anyone in their lives.
What do you do with kids in that kind of situation?