A student-teacher ratio expresses the relationship between the number of students enrolled in a school, district, or education system and the number of “full-time equivalent” teachers employed by the school, district, or system. For example, a student-teacher ratio of 10:1 indicates that there are ten students for every full-time equivalent teaching position. In public schools, the term full-time equivalent (often abbreviated as “FTE”) is a standard measure of teaching capacity that represents both full-time teachers (each full-time teacher is counted as one FTE) and part-time teachers (two half-time teachers, for example, would count as one FTE).
It should be noted that most schools, districts, and states count all “instructional staff” as teachers when calculating student-teacher ratios and full-time equivalencies. For this reason, a school might have 52.5 full-time equivalent teachers, which may include only 40 staff members who might be considered “teachers” in the more narrow or traditional sense of the term. The instructional staff in a given school may include librarians, speech therapists, and other academic-support specialists or licensed teaching staff who may not have traditionally defined classroom-teaching roles. For this reason, a student-teacher ratio of 10:1 does not mean that the average class size in a school is ten students. To better illustrate this issue, for example, one study found that the average difference between student-teacher ratios and average class sizes in a selection of schools was between nine and ten students. In this case, a school with a student-teacher ratio of 20:1 would likely have an average class size closer to 30. For a related discussion, see class size.
Because student-teacher ratios are a general way to measure teacher workloads and resource allocations in public schools, as well as the amount of individual attention a child is likely to receive from teachers, student-teacher ratios are often used as broad indicators of the overall quality of a school, district, or education system. In addition, “ideal” student-teacher ratios will depend on a wide variety of complex factors, including the age and academic needs of the students represented in the ratio (younger children or higher-need student populations typically require more time, attention, and instructional support from teachers) or the experience, skill, and effectiveness of the teachers (highly skilled teachers may be able to achieve better academic results with larger classes than less skilled teachers with smaller classes).
Student-teacher ratios also directly affect per-pupil spending—or the average amount of money spent to educate students in a school, district, or education system. For example, the salaries and benefits paid to teachers and instructional staff can account for up to 75 percent of per-pupil expenditures, so higher student-teacher ratios will typically result in lower per-pupil expenditures.
In recent decades, a wide variety of school-reform strategies and initiatives—at the level of state and federal policy, as well as in individual schools and districts—have focused on decreasing student-teacher ratios as a strategy for improving the academic performance of students. The basic rationale is that teachers with fewer students will be able to devote more time and attention to each student, which will increase their chances of improving learning outcomes. Yet because reducing student-teacher ratios generally requires the hiring of additional teachers, possibly even a significant number of teachers (in the case of states and large school districts), some ratio-reduction policies can entail significant increases in educational expenditures.
One of the desired benefits of lower student-teacher ratios is the increased amount of individual attention that students are more likely to receive when schools have more instructional and support staff per student. In addition to hiring more instructional staff, schools may also use a wide variety of alternative instructional or school-configuration strategies—such as advisories, personalized learning, teaming, or “small learning communities,” to name just a few—that are intended to achieve the same academic results as schools with lower student-teacher ratios. In small learning communities, to use just one example, students are typically paired with teachers, counselors, and support specialists who, over time, get to know students and their specific learning needs well, enabling them to educate the students more effectively. Even though the average student-teacher ratio in a school may not change in small learning community settings, students will be grouped and supported in ways that can potentially reproduce the benefits of lower student-teacher ratios.
Lower student-teacher ratios may also become the target of or rationale for reforms and policies aimed at reducing educational expenditures. For example, reformers and policy makers may use comparisons of student-teacher ratios from place to place, and the results achieved by different systems, as a rationale for justifying higher student-teacher ratios as a mechanism for reducing costs.
Debates related to student-teacher ratios tend to be focused on either educational expenditures or the effects of class size, and on whether simply reducing student-teacher ratios will actually improve academic achievement in a school, district, or education system. Research studies on student-teacher ratios and academic achievement have found mixed results: some indicate that lower student-teacher ratios in schools produce educational benefits for students; others suggest that teaching skill and quality are the main factors, and that hiring more teachers—who may not necessarily be more experienced or skilled—will simply increase educational costs without producing the desired results for schools and students.
In some cases, educators may also disagree over the precise point at which students begin to benefit from lower student-teacher ratios. Some research evidence suggests, for example, that reducing ratios may not have a beneficial effect on student achievement until the average ratio drops below at least 20:1, or that educational benefits are only measurable when student-teacher ratios fall to 18:1 or lower.
The Glossary of Education Reform by Great Schools Partnership is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.