Quality public education: (Most) everyone wants it, yet there is no clear cut, agreed-upon roadmap to achieve it – particularly as public school districts around the country have felt the sting of state funding cuts and shrinking local tax bases.

In recent years, financial challenges have forced many schools to find ways to “do more with less,” often leading to reductions in teaching staff.  In fact, the student-teacher ratio in the U.S. rose to 16.0 for the 2010-11 school year, up from 15.4 the prior year, according to recently released data from the National Council for Education Statistics (NCES)*.

The numbers vary widely from state to state.  For the 2010-11 school year, the student-teacher ratio ranged from a high of 24.1 in California to a low of 11.4 in North Dakota, according to the report.

But as some classrooms may be getting more crowded, room for public misinterpretation is growing – even about what the student-teacher ratio really means.

By definition, the student-teacher ratio reflects the total number of students divided by total number of teachers.  However, as Matthew M. Chingos, Fellow at the Brookings Institution Brown Center on Education Policy, points out, “It is important to note that the student-teacher ratio is not necessarily the same thing as class size.”

Chingos, who has extensively studied the areas of classroom size reduction policies and public perception of school quality, warns against confusing class size with student-teacher ratio.

“In reality, high school classes tend to be larger than elementary school classes, even though the student-teacher ratio for high school is much smaller than for elementary school.” Chingos’ point is illustrated by the NCES data for the 2010-11 school year, which shows the student-teacher ratio for elementary schools was 20.0, while the student-teacher ratio for secondary schools was 12.4.

The student-teacher ratio also depends on schools’ staffing patterns.  For example, a school with an average class size of 20 students may add a special teacher to teach music, which would reduce the student-teacher ratio, but not change the class size.  Or, one high school might have a teacher with four classes per day, while in another high school across town, a teacher may teach five classes per day.  Again, the class size may not change, but the student-teacher ratio would be higher in one school than the other.

Demographics can play a role in student-teacher ratios.  In California, a music teacher might see 100 students in the course of a week (once a week for one hour), while a music teacher in a smaller, rural school in North Dakota might see only 25 students per week – and perhaps also teach art classes at that same school – therefore affecting the student-teacher ratio for that school.

Student-teacher ratios may reflect tradeoffs.  While it is true that one way in which some public school districts are coping with budget pressures is to increase class size, it’s all about tradeoffs, particularly with finances stretched to their limits.  Incremental increases in class sizes can translate into large cost savings – often protecting other programs such as physical education, art, and music programs, school sports teams, and other extra-curricular activities from the chopping block.

Small class sizes – or low student-teacher ratios – do have the potential to boost student performance, says Chingos, but are not the panacea.  Conversely, larger class sizes do not automatically pose a threat to student performance. The decision to make changes to keep a small class size – particularly if it is at the cost of other programs, services, or materials – must be carefully assessed. 

* National Council for Education Statistics (NCES), “First Look” report on Public Elementary and Secondary School Student Enrollment and Staff Counts from the Common Core of Data for the 2010-11 School Year.