"Promise Academy produced gains of 1.3 and 1.4 standard deviations. That’s off the charts. In math, Promise Academy eliminated the achievement gap between its black students and the city average for white students. Let me repeat that. It eliminated the black-white achievement gap.
Over the past decade, dozens of charter and independent schools, like Promise Academy, have become no excuses schools. The basic theory is that middle-class kids enter adolescence with certain working models in their heads: what I can achieve; how to control impulses; how to work hard. Many kids from poorer, disorganized homes don’t have these internalized models. The schools create a disciplined, orderly and demanding counterculture to inculcate middle-class values."