Why this matters
NCES pupil:teacher ratio is enrollment ÷ full-time-equivalent teaching staff. It isn't class size — specialists, resource teachers and coaches pull the ratio down without changing what's happening in a classroom — but a lower ratio generally means more adult attention per student.
What we're seeing
At Cambridge, the student:teacher ratio has fallen 16% over the 5-year window — from 16.1:1 in 2019 to 13.5:1 in 2023. Despite that, the gap vs US average of 15.4:1 has actually widened — from 0.7:1 below in 2019 to 1.9:1 below in 2023.