How Much Does Class Size Matter?

large class size
Photo: Twenty20

Class size is one of the first things many parents think about when considering the quality of a school. Parents are naturally attracted to small class sizes because it seems more likely that the teacher will be able to manage the classroom well and will be able to get to know and serve each child well.

But is this the right way to think about class size? How much does class size really matter?

Lots of studies have looked at the influence of class size on academic progress, social-emotional development, and student motivation. The results suggest that parents should be careful about putting too much emphasis on class size.1

Teachers like small classes

It is true that teachers typically prefer lower class sizes and students often benefit from them. Studies have shown that Tennessee school children learned modestly more each year after the state reduced class sizes, and that eighth graders are more engaged in smaller classes.

However, research also shows that class size matters less to student learning that you might think, and that other factors can often be more important.

After reading several of the studies and reflecting on my own experience in schools, I’d suggest you keep three issues in mind as you consider the importance of class size:

  1. Class size generally matters less than teacher quality.
  2. Smaller classes are more important for some children than for others.
  3. The wider the range of student ability in a class, the more class size matters for all students.

Let’s consider these issues one at a time.

Class size generally matters less than teacher quality

One of the strongest findings from research is that your child will generally be better off in a larger class with a really good teacher than a smaller class with a mediocre one. As long as class sizes aren’t too large, it makes more sense for schools and districts to focus their efforts on attracting and developing great teachers than reducing class size. This is because good teachers are so much better than mediocre teachers at designing instruction, managing classrooms, and motivating students.

Smaller classes are more important for some children than others

If you have two classrooms with equally talented teachers and one has 17 kids and the other has 25 kids, of course the smaller classroom will be better. But since nothing in life is free — the price of admission to that smaller class may be thousands of dollars in private school tuition — it’s important to ask how much better and for whom.

The answer depends in part on your child. The further your child is from the average level of performance in the classroom, whether they’re more advanced or in need of extra support, the more they’ll likely benefit from small class sizes. Additionally, the more social and emotional challenges your child experiences at school, the more they have to gain from smaller classes. If you have a child whose achievement is fairly typical and they’re well adjusted at school and the teachers are good, class size matters less.

The wider the range of student ability in a class, the more valuable small classes are  — for all students

The typical American public school has some students who are two years ahead of grade level, others who are two years behind, and plenty in between. One of the hardest parts about being a teacher is designing and delivering instruction that works for all kids.

The wider the range of student abilities within a classroom, the harder the task for the teacher, The more extreme the differences — for example, if some students are three years ahead and others are three years behind — the more difficult it is for the teacher to serve all children well. Regardless of your child’s particular situation, the wider the range of student ability in a classroom, the more valuable small classes are for everyone.

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How Much Does Class Size Matter?
  1. Peg Tyre has written one of the best summaries of the research about class size. See chapter 3 of her book The Good School: How Smart Parents Get Their Kids the Education They Deserve.