Less Is More
Ask a parent or teacher to name the most important factor in children's learning, and you're likely to hear about small classes. But ask a principal or superintendent, and you may get a different response. Administrators sometimes play down the benefits of reducing the number of students in classrooms. "Research has not conclusively shown that small classes are linked to improved student learning," they might say, or "Learning gains only show up when classes get down to 15 kids."
Well, not quite, say researchers from the Student/Teacher Achievement Ratio project, or Project STAR for short. As part of a two-phase study, the researchers have been tracking classes of 15 to 17 students in 79 schools scattered across Tennessee since 1985. Their efforts make up the largest and longest-lasting experiment ever conducted to examine the effects of small class sizes on student learning and development.
Not only do students in the early grades learn more in smaller classes, the project's investigators say. But they continue to have an edge over the rest of their peers years after they return to normal-sized classrooms.
What's more, they add, the data they have collected are beginning to show that every time a student is added to a classroom, learning is diminished for the rest of the class.
"This is one of the great experiments in education in United States history," Frederick Mosteller, a Harvard University statistics professor, says of the proj~ect. "It definitively answers the question of whether reduction from this size to that size does make a difference, and it clearly does."
But some education researchers are skeptical that Project STAR's findings make the definitive case for small classes. They point out that more than 1,100 studies on class size have been conducted over the years and that the findings have been mixed.
"I don't think a single study proves all that much," says one such skeptic, Herbert J. Walberg, a professor at the University of Illinois at Chicago. "You can find some studies that indicate that bigger classes have better effects on learning."
Walberg also suggests that other kinds of intervention, such as cooperative learning, may be more effective and less expensive. Even if smaller classes do make a difference, critics ask, are they worth the expense?
Testing It Out
Before Project STAR, the landmark study used to argue for small classes was an analysis Gene V. Glass and Mary Lee Smith conducted in the 1970's. They reviewed dozens of studies on the subject and concluded that reducing the number of students in a class does have a modest effect on learning.
Their findings also implied that the benefits would not show up until classes had been reduced to 15 or fewer students. But the study was controversial, partly because it mixed different grade levels and kinds of classes, including graduate seminars and one-on-one tutorials.
When the class-size debate reared its head in the Tennessee legislature several years later, lawmakers decided to test out the hypothesis themselves. Spurred by then-Gov. Lamar Alexander's pro-education agenda, the legislature allocated $3 million to four of the state's top universities to launch Project STAR.
"All educators and parents know that, with fewer children, you can do a better job," says Helen Pate-Bain, who lobbied for the project when she was an associate professor at Tennessee State University. She says that 30 years of teaching high school taught her that. "But when you talk to the people who hold the purse strings, they all said to us that research says that small classes don't make a difference."
"The reason for doing the study was to once and for all show that class size does make a difference," adds Pate-Bain, who is now retired. She later became one of four principal investigators in the project.
Unlike the studies that came before it, Pate-Bain and her partners wanted Project STAR to be a true experiment in the most scientific sense of the word. Investigators decided to focus their efforts on students in kindergarten through 3rd grade, reasoning that small classrooms could have the biggest effect on young learners.
"If you can give a child a good beginning, if they learn to read, nobody can take that away from them," says Pate-Bain, who is also a former president of the National Education Association, which has pushed hard to make smaller classes part of union contracts.
Of the 79 elementary schools that took part in the study, 25 were located in urban areas, 16 were in suburbs, and 39 were in rural areas. To participate, schools had to have at least 57 students in a grade--enough for one small experimental class of 13 to 17 students and two normal-sized classes of 22 to 25 students, one with an aide and one without.
"That way, whatever else might be happening at the school would happen under all three conditions," says Barbara Nye, who is the director of a follow-up study that became the successor to Project STAR.
Students were assigned to their classes randomly.
Through all four years of the study, the researchers found, students in all four grades on average outscored their peers in both types of large-class settings on a battery of standardized tests. Those tests included the Stanford Achievement Test, Tennessee's Basic Skills Criterion Tests, and another basic-skills-type test developed especially for the project.
Students in the inner-city schools appeared to make the greatest leaps. But their counterparts in suburban and rural schools made gains as well.
In reading and mathematics, the size of the gain was about a quarter of a standard deviation. To understand what that means, Mosteller says, think of a child who, without any special treatment, might score at about the 50th percentile on a test. A gain in score of a quarter of a standard deviation would raise that child from the 50th to the 60th percentile. In other words, now 60 percent of the testing population scored lower than that child.
"And we didn't do anything to schools other than reduce class sizes," adds Jayne Boyd-Zaharias, who took part in both Project STAR and the follow-up study.
Having a teacher's aide in the classroom, on the other hand, produced only slight improvement in student achievement.
But Does It Last?
By the end of Project STAR, researchers had collected data on 7,000 students and spent $12 million. But questions arose over whether the documented gains would last. So, with continuing support from the state, the researchers launched a second study.
That project, called the Lasting Benefits Study, is less rigidly controlled than Project STAR. Through it, however, researchers were able to track students after they returned to normal-sized classes in the 4th grade and for years afterward.
In grades 4, 5, 6, and 7, the investigators have thus far found, students who had been in smaller classes in grades K-3 continued to outscore their peers who had been in larger classes. The differences in those scores, however, diminished somewhat as the years went on.
Moreover, the benefits were not limited to reading and math. Students from smaller classes outscored their grade-mates from larger classes in science, social studies, and other subjects, too. Other studies suggest that those students also participated more in class and took part in more extracurricular activities than their peers from larger classes.
Researchers are still tracking more than 4,000 of those students and hope to continue to do so after they leave high school to go on to college or STARt a career. Results on 8th graders are expected to be completely analyzed later this year.
Charles M. Achilles, a principal investigator on both projects, is also analyzing the data to see whether 15 or 17 is a "magic number"--the threshold at which real learning gains STARt to occur--or if any reduction in class size helps. Would adding or taking away a child in a class of 24 or 25 make a difference?
"It looks as though the addition of a child to a class decreases the class's average scores by about about one-tenth of one month," in terms of the expected learning progress, he says. But, he warns, "we're still tinkering with this."
The results from Project STAR and from the early years of the Lasting Benefits Study persuaded the Tennessee legislature to take the plunge and pay for small classes. In 1989, lawmakers set aside funds to reduce class sizes in kindergarten through 3rd grades in 17 of the state's 138 school districts with the highest proportions of poor students.
More recently, the American Academy of Arts and Sciences, spurred by Mosteller's review of the project, has begun to tout the study as proof that small classes matter. The researchers also traveled to London in May to present their findings to educators weighing the matter there.
"It's time that we quit asking the question, 'Does it make a difference?' and begin to ask why it makes a difference and how we can begin to use this information," says Achilles, who is also a professor of educational administration at Eastern Michigan University.
But the question keeps coming up. ERIC A. Hanushek, a University of Rochester economist and public-policy professor, is one of the critics to raise it most recently. Hanushek analyzed 300 studies and concluded that across-the-board reductions in class size are not worth the expense.
Although Project STAR wasn't included in that analysis, Hanushek does have an opinion about the study's findings. "Those people are zealots," Hanushek says of the STAR researchers. The problem with Project STAR, he explains, is that there is not much "value added" beyond the achievement gains that come about in kindergarten. The size of the effect in grades 1 through 3 is about the same.
On the other hand, Hanushek points out, the expense is considerable. "Dropping a class from 25 to 22 students increases classroom expenditures by more than 10 percent," he writes in his 1994 book, Making Schools Work: Improving Performance and Controlling Costs.
Project STAR's investigators counter that Hanushek, in his analysis, looked at overall student-staff ratios. That meant he included in his calculations, for example, librarians and special-education teachers--neither of which figure much in reducing the actual size of classes in a given school.
It is true, they concede, that the greatest gains come in the first year or two that students have smaller classes. But the point, they say, is that those gains remain just as strong as long as classes continue to be small.
The researchers also point out that, by 1st grade, the sample of students in small classes included students who were retained as well as 250 students who had not gone to kindergarten. (Kindergarten attendance was not mandatory in Tennessee at the time.) If anything, the STAR researchers say, their numbers are probably conservative.
They also suggest that, contrary to what Hanushek says, the benefits are cumulative. In kindergarten, 55 percent of the top-scoring classes in the project's sample population were small classes. By 3rd grade, small classes accounted for 78 percent of the top 10 percent.
As for the cost, the STAR researchers point out that reducing the number of students that are held back each year or that require remedial service through the federal Title I program for disadvantaged students translates to cost savings in the long run.
"Is it worth it to spend $1,500 extra for a child not to fail," Nye asks, "rather than spend $10,000 for a child to repeat a grade?"
For More Information
More information on this topic is available from:
Finn, J.D., & Achilles, C.M. (1990). "Answers and questions about class size: A statewide experiment." American Educational Research Journal. 27(3), 557-577.
Glass, G.V., Cahen, L.S., Smith, M.L., & Filby, N.N. (1982). School class size: Research and policy. Beverly Hills, Calif.: Sage Publications.
Hanushek, E.A. (1994). Making schools work: Improving performance and controlling costs. Washington, D.C.: The Brookings Institution.
Mosteller, F. (1995). The Tennessee study of class size in the early school grades. Initiatives for Children, American Academy of Arts and Sciences, Cambridge, Mass.
Nye, B.A., Boyd-Zaharias, J., Fulton, B.D., et al. (1994). The lasting benefits study: Grade 7 technical report. Center for Research in Basic Skills, Tennessee State University, Nashville, Tenn.
Pate-Bain, H., Achilles, C.M., Boyd-Zaharias, J., & McKenna, B. (1992). "Class size does make a difference." Phi Delta Kappan. 74(3), 253-56.