For five years, Stephanie Dua had a close-up view of the chan-ges under way in American public education.

As chief executive of New York City’s Fund for Public Schools, she was responsible for raising private funds to support re-forms to public education. These ranged from preparing teachers for Common Core, which will set standards in English and maths, to improving school lib-raries and starting a helpline for parents. But in 2011, she decided to join the city’s swelling ranks of education professionals turned entrepreneurs.

Under Mayor Michael Bloomberg, New York has become a laboratory of educational experiment. In ef-forts to improve the city’s schools, which vary wildly in quality, he has encouraged entrepreneurs and innovators in education to apply their ideas to education. Many have found a home as well as funding and talent in the city’s flourishing tech and start-up scene.