Approved April 2014
NCTE has long-established positions on class size for English language arts teachers. In 1960 it adopted a policy that secondary teachers of English should teach a maximum of 100 students per day, and that elementary teachers should have a comparable load. In 1971 it passed a resolution to inform local, state, and national administrators and policymakers about this policy. In 1983 and again in 1995 there were resolutions urging more attention to the issue of class size. And in 1999 NCTE issued a position statement on class size and teacher workload.
Today public schools employ 250,000 fewer people than before the recession of 2008–09, while enrollment has increased by 800,000, and class sizes in many schools are at record highs (Rich, 2013). Recent research tells us why this matters:
What Is Class Size?
In research on early elementary school students, small classes usually mean fewer than 20 students, while for high school students the definition of “small” classes is usually somewhat larger. There are similar variations in what constitutes small classes for college writing instruction. In addition to the ambiguity about how many students constitute a smaller class, researchers use different strategies for assigning a class-size number. It can mean the number of students enrolled in the course, the number of students completing the course, or the number of students completing major course assignments (Arias & Walker, 2004). Furthermore, there is a shifting relationship between class size and teacher workload. Reducing class size can, for example, increase teacher workload if the number of students per class is lowered but teachers are assigned one more class per day.
Overall, research shows that students in smaller classes perform better in all subjects and on all assessments when compared to their peers in larger classes. In smaller classes students tend to be as much as one to two months ahead in content knowledge, and they score higher on standardized assessments. It is worth noting, however, that some studies analyze student assessment results in terms of individual student performance and others in terms of class-wide aggregated performance, which can obscure the differences in individual students’ performances.
These positive effects of small class sizes are strongest for elementary school students, and they become more powerful and enduring the longer students are in smaller classes. That is, students who have smaller classes in early elementary grades continue to benefit from this experience even if they are in larger classes in upper elementary or middle school (Bruhwiler & Blatchford, 2011; Chingos, 2013).
Despite the generally positive effects of smaller classes, the benefits are not consistent across all levels and populations. Small classes make the biggest difference for early elementary school students, while for many high school students smaller classes do not make a significant difference in academic performance. However, for minority and at-risk students as well as those who struggle with English literacy, smaller classes enhance academic performance. Class size also shapes the quality of writing instruction at all levels, including college, because smaller classes are essential for students to get sufficient feedback on multiple drafts. Not surprisingly, smaller writing classes increase retention at the college level (Blatchford et al., 2002; Horning, 2007).
Academic performance is important, but it is not the only measure of student success. In the area of student engagement, findings consistently show the value of small classes. Students talk and participate more in smaller classes. They are much more likely to interact with the teacher rather than listen passively during class. Not surprisingly, students describe themselves as having better relationships with their teachers in smaller classes and evaluate both these classes and their teachers more positively than do their peers in larger classes. Students display less disruptive behavior in small classes, and teachers spend less time on discipline, leaving more time for instruction. Specifically, teachers in smaller classes can diagnose and track student learning and differentiate instruction in response to student needs. In smaller classes students spend less time off-task or disengaged from the work of the class, and they have greater access to technology. Research also suggests that smaller class sizes can help students develop greater ability to adapt to intellectual and educational challenges (Bedard & Kuhn, 2006; Dee & West, 2011; Fleming, Toutant, & Raptis, 2002).
The benefits of smaller classes extend beyond test scores and student engagement. In addition to the longer-term positive attributes of small class sizes in the early grades, benefits include continued academic and life success. Researchers have found that reducing class size can influence socioeconomic factors including earning potential, improved citizenship, and decreased crime and welfare dependence. The beneficial effects of being assigned to a small class also include an increased probability of attending college. This benefit is greatest for underrepresented and disadvantaged populations. While the increased probability for all students is 2.7%, it is 5.4% for African American students and 7.3% for students in the poorest third of US schools (Dynarsky, Hyman, & Schanzenbach, 2013; Krueger, 2003).
Teacher quality has, for some time, been recognized as the most important variable in the academic success of students. Recruiting and retaining effective teachers has become increasingly important as school districts impose mandates about student test scores and overall academic performance. Class size has an effect on the ability to retain effective teachers because those with large classes are more likely to seek other positions. Research indicates, however, that instead of rewarding effective teachers by decreasing their class size, administrators often increase the class sizes of the most effective teachers in order to ensure better student test scores (Barrett & Toma, 2013; Darling-Hammond, 2000; Guarino, Santibañez, & Daley, 2006).
The Cost Factor
One of the most common arguments against smaller class sizes is financial. School districts claim that they cannot afford to reduce the size of classes because it would be too expensive. However, it is also expensive when students leave public schools to attend private ones. Research shows that class size is a significant factor in parents’ decisions to send their children to private schools. Despite the enormous emphasis on test scores in public schools, parents report little interest in these scores when choosing a school. Instead, two of the top five reasons parents give for choosing a private school are “smaller class sizes” (48.9 %) and “more individual attention for my child” (39.3%). The other three reasons are better student discipline, better learning environment, and improved student safety, all of which are influenced by class size (Kelly & Scafidi, 2013).
Class size is a major factor in student learning. To be sure, it is one of several important factors, and more research is needed to determine how it interacts with phenomena such as teacher quality and context, but existing research should guide policy decisions in several ways.
- Do not conflate class size and teacher workload.
Class size can refer to enrollment in or completion of a given class or program of study, and each of these has different implications for a teacher’s workload. If a large number of students enroll but do not complete a course, for example, the ratio of class size to workload will shift depending upon whether enrollment or completion is considered. Furthermore, requiring teachers to teach more classes with smaller numbers of students in each does not constitute a decrease in workload.
- Recognize that the benefits of reduced class size are not uniform across all grades and populations.
Although more research is needed to understand the full effect of class size, existing research shows that younger students, at-risk students, and special-needs students receive greater benefit from small classes than other populations.
- Consider the differential effects of class size across the disciplines.
Most research on class size does not distinguish among disciplines, so it is easy to assume that an increase or decrease in class size will have the same effect in every classroom. However, a class that assesses student learning with multiple choice tests may not receive as much benefit from a reduction in class size as a class that assesses student learning with written essays.
- Use multiple measures to evaluate the effects of reducing class size.
Since class size interacts with several dimensions of learning that extend beyond what can be measured with a standardized test, it is important to use several different measures to determine the effects of making classes smaller.
Arias, J. J., & Walker, D. M. (2004). Additional evidence on the relationship between class size and student performance. Journal of Economic Education 35(4), 311–329.
Barrett, N., & Toma, E. F. (2013). Reward or punishment? Class size and teacher quality. Economics of Education Review 35, 41–52.
Bedard, K., & Kuhn, P. J. (2006). Where class size really matters: Class size and student ratings of instructor effectiveness. Economics of Education Review 27, 253–265.
Blatchford, P., Goldstein, H., Martin, D., & Browne, W. (2002). A study of class size effects in English school reception year classes. British Educational Research Journal, 28(2), 169–185.
Bruhwiler, C., & Blatchford, P. (2011). Effects of class size and adaptive teaching competency on classroom processes and academic outcome. Learning and Instruction 21(1), 95–108.
Chingos, M. M. (2013). Class size and student outcomes: Research and policy implications. Journal of Policy Analysis and Management 32(2), 411–438.
Darling-Hammond, L. (2000). Teacher quality and student achievement: A review of state policy evidence. Educational Policy Analysis Archives 8.
Dee, T., & West, M. (2011). The non-cognitive returns to class size. Educational Evaluation and Policy Analysis 33(1), 23–46.
Dynarsky S., Hyman, J. M., and Schanzenbach, D. W. (2013). Experimental evidence on the effect of childhood investments on postsecondary attainment and degree completion. Journal of Policy Analysis and Management 32(4), 692–717.
Finn, J. D., & Achilles, C. M. (1999). Tennessee’s class size study: Findings, implications, misconceptions. Educational Evaluation and Policy Analysis 21(2), 97–109.
Fleming, R., Toutant, T., & Raptis, H. (2002). Class size and effects: A review. Bloomington, IN: Phi Delta Kappa Educational Foundation.
Guarino, C. M., Santibañez, L., & Daley, G. A. (2006). Teacher recruitment and retention: A review of the recent empirical literature. Review of Educational Research 76(2), 173–208.
Horning, Alice. (2007). The Definitive Article on Class Size. WPA: Writing Program Administration 31(1/2), 14-34.
Kelly, J., & Scafidi, J. (2013). More Than Scores: An Analysis of How and Why Parents Choose Schools. Friedman Foundation for Educational Choice. Retrieved from https://www.edchoice.org/research/more-than-scores/
Krueger, A. B. (2003). Economic considerations and class size. The Economic Journal 113 (485), F34–F63.
Rich, M. (2013, December 21). Subtract teachers, add pupils: Math of today’s jammed schools. The New York Times. Retrieved from http://www.nytimes.com/2013/12/22/education/subtract-teachers-add-pupils-math-of-todays-jammed-schools.html
Class sizes have been in the news recently. On Thursday the Labour party pledged that if elected it would cap class sizes at 30 for pupils aged five to seven years.
By contrast, last week the head of the OECD Program of International Student Assessment (Pisa) surveys, Andreas Schleicher, set out the seven big myths about top-performing school systems, with myth number four being that small classes raise standards. This can’t be right, he argues, because high-performing education systems like those in east Asia focus on better teachers, not class sizes.
Ed Miliband: Labour would restore Blair-era cap on class sizes
These two attitudes reflect opposite sides of a longstanding and angry debate which resurfaces at regular intervals. On the one hand we have teachers, unions, parents and some academics arguing that smaller classes allow better teaching and learning; on the other are many policymakers, politicians and advisers, as well as some academics, who argue that class size is not important. Despite the Labour party pledge, my impression is that this latter perspective is gaining ground. As well as the OECD, the view is reflected in the influential Sutton Trust toolkit, and in a number of weighty reports by, among others, McKinsey & Company, the Grattan Institute, and the Brookings Institution.
How do we reconcile these two different approaches? Are teachers wrong and self-serving, as some commentators imply? To address this question we need to examine the evidence on the relationship between class size and pupil performance.
As someone who has researched this for some time, I am struck by how those in favour of larger classes rely on three main sources of data: cross-national comparisons, “meta-analyses” and econometric analysis. Yet all of these offer only a partial view and are not conclusive on the causal role of class size.
Results from Pisa are a case in point. These show that students in east Asian regions like Shanghai and Hong Kong do very well on school tests and also have relatively large classes; it is therefore concluded by many that class size is not important to academic achievement. But the flaw in this argument is that there are a host of reasons why high-performing Asian education systems do well, including high levels of parental support, cultural factors that favour education, and the prevalence of private tutoring. The causal effect – or not – of class size therefore cannot be inferred.
Class size does matter for the younger pupils in the first two to four years in school
So called “meta-analyses”, such as the well-known one by professor John Hattie have also been persuasive. They involve large-scale statistical analysis of multiple studies which address the effects of class size. The conclusions have generally been that class size does not have a major influence on student learning. Yet often these analyses are based on studies of such varying quality, and with variable parameters – age of pupils and research design, for example – that it is difficult to arrive at sound conclusions.
A similar problem exists with econometric analyses – studies by economists who often take measures of class size, or more usually pupil-teacher ratios (which is not the same thing), and develop statistical models of effects that take little account of what actually happens in school.
Interestingly, these sources of data are all secondary analyses; that is, they use data collected by other people and are often not designed to study class size at all.
What is needed are dedicated studies of class-size effects which carefully control for potentially confounding factors like pupil and teacher characteristics. There are very few such studies. Perhaps the two most reliable and large-scale ones – the Student/teacher achievement ratio (Star) experimental project from Tennessee, and the Class size and pupil adult ratio (CSPAR) longitudinal study, which I directed at the Institute of Education (IoE) – arrive at similar conclusions: class size does matter for the younger pupils in the first two to four years in school, and small classes are particularly beneficial for the more disadvantaged and initially lower-attaining pupils. It is sometimes argued that class sizes have to become smaller than 20 for any noticeable effect, but in the IoE study we were able to show that there was no such threshold; the effects of class size continued in a linear way across the range of class sizes.
But in any case, the debate over class size has become tired and formulaic, and is hampered by significant limitations. One is that the focus on class size and academic performance overlooks the effect of class size on other aspects of classroom life, such as relationships, discipline and catering for pupils with special educational needs. Again, there are few studies, but careful moment-by-moment systematic observation of pupils shows that class size affects the amount of individual attention pupils receive, and their engagement and active involvement in class.
Class sizes and teaching are not mutually exclusive
In a recent IoE study we found that lower-attaining secondary pupils were more likely to be off task in larger classes when compared to middle- and high-attaining pupils. Intriguingly, in high-performing east Asian countries like China, Hong Kong and Taiwan, there has been a move recently to introduce smaller classes. This is not to improve academic attainment, but to help with a move from teacher-directed to student-centred approaches that aim to meet individual pupils’ diverse educational needs, and to develop critical thinking and collaborative approaches. So performance on tests is not the only worthwhile educational outcome; there are other pupil outcomes and classroom processes that can be influenced by class size.
The second limitation of much of this debate is that it sets up the issue as a binary choice: either invest in class sizes or in teaching. But these are not mutually exclusive.
All teaching and learning takes place within a context, and one important feature of school classrooms is the number of pupils in a class. We can all agree that the quality of teaching is vital, but smaller classes can help teachers provide a more effective education. This is appreciated far more in east Asia than the west, as is the realisation that the benefits of class-size reduction will not happen automatically, but will require careful attention and professional development if we are to make the most of the opportunities that smaller classes offer. Instead of focusing on the relationship between class size and pupil attainment, we should be looking at the relationship between class size and effective teaching.