Student/teacher ratios tend to be higher in public schools with larger enrollments than in public schools with smaller enrollments.

The ratio of students to teachers, which is sometimes used as a proxy measure for class size, declined between 1990 and 2005 from 17.6 to 16.1 students per teacher for all regular¹ schools (see table 33-1). This pattern changes, however, when public elementary, secondary, and combined schools are examined separately.

The student/teacher ratio for regular public elementary schools declined from 1990 through 2005 (from 18.2 to 15.8), with most of the decline occurring after 1996. Generally, elementary schools in each enrollment category showed similar patterns except in the largest schools (1,500 students or more), where the student/teacher ratio fluctuated between 19.6 and 21.2 over this period.

In contrast, student/teacher ratios for all regular public secondary schools increased between 1990 and 1996 (from 16.7 to 17.6) and then declined to 16.8 in 2005. Secondary schools in each enrollment category showed similar patterns.

In regular public combined schools (schools that include both elementary and secondary grades), student/teacher ratios were lower in 2005 (15.3) than in 1990 (15.8). This pattern varied by the school enrollment: the student/teacher ratio for the largest enrollment category was higher in 2005 than in 1990, the student/teacher ratios for the middle three enrollment categories were lower in 2005 than in 1990, and the student/teacher ratio for the smallest enrollment category was of similar magnitude in 2005 and 1990 (11.1 versus 11.0).

In every year from 1990 through 2005, the student/teacher ratio was positively associated with the enrollment for elementary, secondary, and combined regular public schools: the student/teacher ratio for any given enrollment category was always larger than that of any smaller enrollment category. For example, in 2005, regular secondary schools with 1,500 students or more enrolled 6.6 more students per teacher, on average, than regular secondary schools with enrollments under 300.

¹ Regular schools include all schools except special education schools, vocational schools, and alternative schools. Charter schools can be of any school type. (back to text)