The number of public school students for every full-time teacher in California was 23.4 during the 2011-12 academic year, almost 50 percent above the national average of 16 students per teacher. The lowest student-teacher ratio was in Vermont with 10.7 students per teacher.
The National Center for Education Statistics released in October 2013 a preliminary report on all the public schools in the country during the 2011-12 school year. Table 2 which looks at student-teacher ratios in every state caught my eye. It’s calculated by counting up all the students and dividing by all the full-time teachers (or full-time equivalent) teachers. (See Table 2 at the bottom of this post).
My first instinct is that these numbers are misleading. You might well have 30 students in a classroom, as many public schools do in New York City, and yet New York States can still post an overall ratio of 12.9. That’s because there may be lots of specialist teachers, from speech therapists to music teachers, that aren’t a daily presence in the classroom but still count toward lowering the ratio.
I’ve heard from researchers that the United States is obsessed with class sizes and puts a lot of resources into throwing more teachers into schools to lower these ratios, whereas other countries might hire fewer but more qualified teachers. For example, the typical classroom in Japan has more than 30 students. See this OECD explainer on class sizes around the world.
Background Reading on Class Sizes
Examining the effect of class size on classroom engagement and teacherepupil interaction: Differences in relation to pupil prior attainment and primary vs. secondary schools by Peter Blatchford, Paul Bassett, Penelope Brown