One factor keeping private schools head and shoulders above public in terms of personal attention to students is allotting more time to teachers, both through reducing class size and allowing teachers more free periods during the day.

"What Cambridge [public school system] needs is more time for professional development," Miller says. "Teachers need time to get together professionally, with their colleagues, in workshops, to go to meetings."

This, she explains, gives teachers a chance to collaborate, support each other and share strategies.

The school district has actually entered into a re-negotiation of teacher contracts, to consider an amendment that would pay teachers for a longer school day.

The current contract requires teachers to be in the school building 15 minutes before the bell in the morning, and to stay 10 minutes after the afternoon bell. They are paid only for this time.

"Very few teachers work just those hours," Walser says.

Harshbarger says he would like students, too, to spend more time at school.

"They need to offer extended-day programs, meaning drama, art, athletics, science programs, for all students after school," Harshbarger says.