From today's NYT, an article called "Taking sides on New York's Chancellor."
The chancellor is NYC's version of a superintendent, but the chancellor is appointed by the mayor. The article describes how some view the chancellor as an innovator willing to take on the teachers' union, while others view him as an "arrogant outsider" who will not consider the views of parents and who values "law degrees over teaching experience when selecting his top deputies."
Changes have included new small and charter schools, changes in admission to gifted programs and data-driven experiments.
As for results- strangely, while state test scores have risen, that is not the case for the national tests taken by eighth graders. The article does not discuss why both national and state tests would not show improvement.