How would Chicago school district know what worked and what didn’t? With foundation help, the University of Chicago launched the Consortium on School Research, where research superstars spent years studying what was going on in Chicago schools. At the same time, Chicago foundations, nonprofits organizations, and educators focused enormous attention on improving the teaching force. Little by little, they all came to the conclusion that unless principals were prepared to lead improvement, all other improvement efforts were futile. So Chicago adopted as its primary improvement strategy the recruitment, development, and support of school leaders and has one of the nation’s model principal preparation programs, Urban Education Leadership at the University of Illinois-Chicago...