What the class size research REALLY says.
As school system budgets tighten, more journalists find themselves writing about—and misinterpreting the research on—class size. Nearly every education writer knows about Project STAR, the only large-scale, random-assignment experiment that has been conducted on class size. Over four years in the late 1980s in Tennessee, researchers assigned children in 79 schools to classrooms ranging from 13 to 25 students. They found significant academic advantages in reading and math for students in small kindergarten and first-grade classes, and the effects diminished in second and third grades. We do not know much about is what kind of difference class size makes outside the parameters of that experiment, at least not with the certainty that comes with the methodological rigor of an experiment like STAR.
To nail down “what the research says” about class size, I contacted three authorities on the topic: Eric Hanushek at Stanford, Thomas Dee at Swarthmore and Beth Graue at University of Wisconsin-Madison. This issue, like nearly any in education, divides people somewhat; I think it’s fair to say that Graue and Dee think reducing class size has more merit than Hanushek does. But they all agree that it is not accurate to extrapolate and say, as some do, that because of STAR we know that class size “only matters” in kindergarten and first grade. Some quasi-experimental studies show benefits of smaller classes; some do not. But there isn’t high-quality evidence to confirm one way or another. There has not been another study the likes of STAR, and in this climate—small class size is out of favor among national reformers, and it is very expensive—I am not sure we will see one, though some researchers would like to make that happen.
In my gut, I cannot help but think the number of kids in a room matters in a variety of ways (what sort of assignments teachers choose to give, how connected students feel to their teachers) when we are talking about big differences in size. To take an extreme example: Just because nobody has studied what would happen if we increased the size of an eighth-grade math class from 28 to 58 doesn’t mean the outcome would be pretty. Of course, on average across a big district, class sizes usually increase only a couple of students at a time. But in individual schools and classrooms, big disparities in class size can happen. We do not have much research on this kind of thing; Dee recommends a study from the early 1990s by Joshua Angrist in Israel, where a maximum class size of 40 made for interesting comparisons. (Forty kids in a grade? One class of 40. Forty-one kids? A class of 20 and another of 21.) For those interested in looking at larger classes than evaluated in STAR, Graue recommends the work of Peter Blatchford in the U.K., who compared classes in the mid-20s to those above 30 students.
Hanushek points out that an issue of key importance is how teachers are hired (in the case of class-size reduction) or fired (in case of increases). He suggests that changes in teacher quality borne of such decisions matter as much as—probably more than—the number of children in the room. If a district reduces class size without a pool of good teachers to draw from, why would you expect improvement? If a school increases class size and has to get rid of teachers with no regard to their effectiveness, the big classes might matter less than losing good educators.
This is all to say, be careful about how you represent the research—only STAR represents the so-called gold standard of research, and even that has its limitations. I suppose “We don’t know if it matters” is not a great line to stick in your story when the school board is debating whether to enlarge classes. If this is an issue in your area, do some shoe-leather reporting comparing classrooms and give qualitative examples. Did a teacher whose classes got bigger stop assigning essays when she felt like she had too many to grade? To what degree do teachers attribute differences in classroom climate to the number of students versus the other myriad factors? I could go on; there is a lot to look at. While doing so, remember that there is a difference between a teacher who says he would leave if his class were significantly larger and one who actually does so.
To nail down “what the research says” about class size, I contacted three authorities on the topic: Eric Hanushek at Stanford, Thomas Dee at Swarthmore and Beth Graue at University of Wisconsin-Madison. This issue, like nearly any in education, divides people somewhat; I think it’s fair to say that Graue and Dee think reducing class size has more merit than Hanushek does. But they all agree that it is not accurate to extrapolate and say, as some do, that because of STAR we know that class size “only matters” in kindergarten and first grade. Some quasi-experimental studies show benefits of smaller classes; some do not. But there isn’t high-quality evidence to confirm one way or another. There has not been another study the likes of STAR, and in this climate—small class size is out of favor among national reformers, and it is very expensive—I am not sure we will see one, though some researchers would like to make that happen.
In my gut, I cannot help but think the number of kids in a room matters in a variety of ways (what sort of assignments teachers choose to give, how connected students feel to their teachers) when we are talking about big differences in size. To take an extreme example: Just because nobody has studied what would happen if we increased the size of an eighth-grade math class from 28 to 58 doesn’t mean the outcome would be pretty. Of course, on average across a big district, class sizes usually increase only a couple of students at a time. But in individual schools and classrooms, big disparities in class size can happen. We do not have much research on this kind of thing; Dee recommends a study from the early 1990s by Joshua Angrist in Israel, where a maximum class size of 40 made for interesting comparisons. (Forty kids in a grade? One class of 40. Forty-one kids? A class of 20 and another of 21.) For those interested in looking at larger classes than evaluated in STAR, Graue recommends the work of Peter Blatchford in the U.K., who compared classes in the mid-20s to those above 30 students.
Hanushek points out that an issue of key importance is how teachers are hired (in the case of class-size reduction) or fired (in case of increases). He suggests that changes in teacher quality borne of such decisions matter as much as—probably more than—the number of children in the room. If a district reduces class size without a pool of good teachers to draw from, why would you expect improvement? If a school increases class size and has to get rid of teachers with no regard to their effectiveness, the big classes might matter less than losing good educators.
This is all to say, be careful about how you represent the research—only STAR represents the so-called gold standard of research, and even that has its limitations. I suppose “We don’t know if it matters” is not a great line to stick in your story when the school board is debating whether to enlarge classes. If this is an issue in your area, do some shoe-leather reporting comparing classrooms and give qualitative examples. Did a teacher whose classes got bigger stop assigning essays when she felt like she had too many to grade? To what degree do teachers attribute differences in classroom climate to the number of students versus the other myriad factors? I could go on; there is a lot to look at. While doing so, remember that there is a difference between a teacher who says he would leave if his class were significantly larger and one who actually does so.
posted by Linda Perlstein at
2:38 PM
7 Comments:
I've long susspected that the direct impact on teachers via the grading load is a huge issue here, and the consequences that you mention here.
But I've never seen any research on that.
As teacher, I've had classes that varried in size by 50% (i.e. 25 vs. 38) in a single semester. Same grade, same course. The larger class was more tiring for me, and -- obviously -- there was 50% more work in terms of grading papers, meeting with students for extra help, trying to contact parents, etc..
I don't know what would happen if I had had an average of 27 kids and then had that upped to 35+ over a small number of years. Would I have changed the kind of assignments I gave, the number, or the amount of feedback?
To play devil's advocate, I should point out that Montessori education actually encourages larger class sizes. Because of the mixed age groups and emphasis on independence, it works well. I don't know if there have been any studies on this. It would be an interesting comparison if there were.
Some of the best teaching I have seen has been in China and Japan where class sizes are often double or more of those in the U.S. But teaching loads are also about half of what they are here. Isolating class size as the lone variable as in STAR makes for interesting research, but what we really care about is how to improve learning in the most economical way possible. So the real question is: What combination of class size and teacher prep time gives the best results for the least resources? Posing the question this way also has the practical effect of depoliticizing the class-size issue that clouds the issue. Unions can abandon their knee-jerk opposition to large class sizes as just another teacher-bashing tactic. Cash strapped school boards would have harder time cherry-picking data to justify increasing class size with no adjustment to teacher work load.
@Carl, learning IS the issue here, I totally agree with you. I also agree that this is one of the biggest issues for the teacher unions, and one that - at least i in Sweden - has been left out in the discussions about school and teachers for a very long time. As I see it there has to be a limit somewhere, a limit for what is reasonable in respect to what tasks you are expected to performe in addition to the definition of the teacher job in itself. There has to be some kind of correlation between the amount of time teachers are able to spend preparing and evalutaing their students learning, hasn´t there?
Schools is Japan and in Sweden are on the tracking systems. That means those larger classes are made up of cream of the crop kids. Also, the STAR report dealt with primary grades. It is like comparing apples to oranges when the discussion moves from kindergarten to second grade or beyond. Teachers are struggling with increasing class sizes. The frustration comes from wanting and attempting to provide students with everything you've given to previous smaller classes. The districts often dream up new programs that are supposed to help but, end up robbing the teacher of valuable instructional time. Its really a no brainer. Less kids = better instruction. Ask any private school what their teacher/student ratio is. Ask them why they stick to 1 to 15.
It would be interesting to correlate class size with teacher burn-out. How many teachers who LEAVE the profession had large classes?
As a first grade classroom teacher for 7 years, I found that teachers are able to conduct best practice procedures (i.e., small group instruction, conferring with students, etc) and teach to students’ individual needs and learning styles when given a manageable class size. Assignments can be project and inquiry based and teachers are able to effectively use alternative assessment for evaluation. Students also benefit from a more intimate learning environment. Authentic conversation and small group work can be the basis for everyday learning. A current analysis of long-term studies and recent grassroots research reveals class size does indeed have a major impact on student achievement, behavior, and attention (Bracey, 1995). “Smaller class sizes, complemented by diverse teaching methods, create better student performance, more positive attitudes and fewer discipline problems,” as explained in the article Class Reduction in Freshman English Classes (1992). Policymakers need to realize that smaller class sizes does not only effect the achievement seen in standardized tests. Teachers and students suffer when class sizes have 25 to 20 students. Reducing class size is one of the many reforms needed to ensure that teachers and students are successful.
Post a Comment
Considerate comments are welcome. Uncivil remarks will be deleted. Anonymous comments -- including those unaccompanied by the author's first and last name -- are not permitted.
Subscribe to Post Comments [Atom]
Links to this post:
Create a Link
<< Home