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Does Class Size Really Matter?

With Over 60 percent of school districts considering staff reductions to balance budgets, class size is likely on many educators' minds.

With Over 60 percent of school districts considering staff reductions to balance budgets (Kober & Renter, 2011), class size is likely on many educators' minds. With money tight, schools are seeking to focus available funds on those policies and programs most likely to have a positive impact on student learning. Although the effects of class size have been debated for decades, Tennessee's STAR project in the late 1980s seemed to settle the argument. However, while the STAR project found significant improvements in student learning when class size was reduced for kindergarten through third grade (Word et al., 1990), the body of research on class size suggests a more complex picture of the relationship between class size and student achievement.

What's the Magic Number?

What many teachers, administrators and parents would like to know is the magic number for each grade level—the perfect number of students to have in a classroom. As with many education conundrums, however, magic is conspicuously absent from the class size research.

The number that seems to come up most often in the research is 15. An early meta-analysis conducted by Smith and Glass found no difference in learning outcomes from reducing classes from 40 to 20, but found significant differences when classes were reduced from 20 to 15 students (Hattie, 2005). In the STAR project, the "small" classes enrolled between 13 and 17 students (Word et al., 1990). Studies that involve class sizes being reduced to 20 students or more, and studies of instances in which substantial numbers of teachers were hired simultaneously in order to reduce class sizes, have generally not found significant effects on student learning (Hattie, 2005).

Capitalizing on Small Class Sizes

The impact of small classes, therefore, is more complex than merely the number of students present in the room. Research and common sense suggest that teachers with smaller class sizes have more time to spend with individual students, that they spend less time managing student behavior, and that they are thus able to implement instructional methods that engage students in learning. Teachers, however, do not necessarily change their teaching strategies when they have fewer students in the classroom. Reductions in class size, therefore, need to be accompanied by extensive professional development efforts so that teachers can improve their effectiveness and thus capitalize on smaller class sizes (Hattie, 2005).

Given that reducing class size alone is an expensive classroom intervention, districts must consider whether it is the most cost-effective way to invest funds (Whitehurst & Chingos, 2011). Unfortunately, there is no research in the United States that specifically compares class size reductions to other investments in terms of the impact on student learning. Comparisons across studies, however, suggest that while class size reduction can contribute to improved student achievement, it raises achievement less—and is less cost-effective—than other alternative classroom investments (Whitehurst & Chingos, 2011).

Despite some conflicting evidence, there certainly are some lessons to be gleaned from the class size research:

  • Class size reductions seem to be most effective in the early grades, specifically kindergarten and first grade (Whitehurst & Chingos, 2011). Focusing class size reduction efforts on these grades, then, may be more likely to affect student learning positively than reducing class size in other grades.
  • Students with less effective teachers will likely benefit from having reduced class size. The learning in classrooms with more effective teachers is less impacted by class size (Whitehurst & Chingos, 2011). Providing smaller classes for less experienced teachers as they develop their teaching skills, therefore, may provide a better educational experience for students in these classrooms.
  • An underreported finding from the STAR project is the effect of small classes on student grade retention. The researchers found that a relatively smaller percentage of students in the small classes repeated a grade each year when compared to students placed in regular classrooms of 22 to 25 students. As grade retention is linked in the research to an increased likelihood of dropping out of school, this finding may be particularly important for districts striving to increase graduation rates (Word et al., 1990).
  • Teachers like having small classes. Studies that report on teachers' attitudes about small classes have found very positive responses from educators. Teachers believed they cover more content in greater depth and have fewer discipline problems with small classes, though the data often did not support such beliefs (Hattie, 2005). Studies also indicate that teachers with smaller classes report less stress (Hattie). While there is not a substantial amount of research specifically on the relationship between class size and teacher retention, it seems possible that creating a less stressful work environment for teachers might increase the likelihood that they will stay in the profession. Reducing class size is expensive, but hiring and training new teachers is expensive as well. Additional research is needed to determine the effects of class size on teacher retention.

In short, the body of literature on class size reduction includes conflicting data. In making decisions on class size policies and practices, however, administrators can look to the research to guide them in setting priorities and selecting interventions that will benefit the students, parents and classroom teachers in their districts.

See related article: Reports Offer Some Answers

Laurene Johnson is a doctoral candidate and teaching/research assistant at Syracuse University.