As the nation’s new president and members of the 111th Congress begin their work in Washington, they might consider the following:
You ran on a platform that included improving our nation’s schools. Our students’ test scores lag behind those of our international trading partners, and our top students in math and science fall far behind the top European and East Asian students who will be the next generation of engineers, scientists, innovators, and business leaders. All of that bodes poorly for our nation’s future international competitiveness.
Throughout your campaign you pledged to reverse that slide. As you anticipate making good on that pledge, you continue to hear a lot about the one research finding that has repeatedly been shown to work: reducing class size.
But the story is not that simple.
It’s true that many studies have shown the benefits of smaller class sizes — including random experiments like the Student Teacher Achievement Ratio Project conducted in 79 elementary schools in Tennessee, which assigned children to either small or regular-size classes, as well as large-scale analyses of small and large classrooms that have occurred naturally. Although researchers may quibble over the exact magnitude of gains associated with smaller classes — or the means by which small classes bring about such gains — few of them disagree with the basic fact that smaller classes result in higher average achievement.
By reducing elementary-school classes from 23 students to 15, achievement, as measured by standardized exams like the Stanford Achievement Test, increases about 7 percent on average. And the longer students are in smaller classes, the greater their achievement gain is.
So as Barack Obama and members of Congress try to fulfill their pledges of closing the international achievement gap, they can count on doing that by cutting enrollments from 22 to 26 children per classroom to 13 to 17, or by increasing the ratio of staff to children in those classes.
But what if, rather than closing America’s international achievement gap, our nation’s leaders had a different education goal in mind: to reduce our domestic achievement gap, the one that separates black and white, rich and poor? In fact, our new president has pledged to do just that. Will reducing class size accomplish that goal, too? Will smaller classes raise the achievement levels of the poorest-performing students — those who are disproportionately minority and low income?
The signs are that it will not. In fact, it is possible that smaller classes will actually widen the domestic achievement gap between the haves and have-nots.
How can a policy help narrow the gap between America’s top students and those of its trading partners, and yet widen the gap between poor and minority American children vis-à-vis their middle-class white and Asian-American classmates? The answer is that many educational interventions, like reductions in class size, don’t just increase the average achievement for all groups of students. They also increase the variability in achievement. In other words, children become more dissimilar as a result of the intervention; their scores spread further away from one another. That greater variability can be seen among children in the same classroom, or among children in different schools and school districts.
Reductions in class size show that effect dramatically: Even as all children gain from being in smaller classes, the “haves” often gain more than the “have-nots.” In fact, when placed in smaller classes, children in the top 10 percent of the score distribution often gain two to four times more than those in the bottom 10 percent. The result is that even though all students make gains in smaller classes — including the lowest-scoring students — the highest-scoring students make bigger gains.
The net result can be a widening of the achievement gap between rich and poor students, and between minority and nonminority students. So, as class-size reduction helps our top students gain ground on the top students in other countries, it also helps further distance them from our own lowest-scoring students, exacerbating an achievement gap that is already large to begin with.
No one knows for certain why high-ability kids do better in smaller classes. One plausible explanation is that the highest-scoring students engage in learning opportunities and take advantage of the teaching practices that take place in smaller classes more than their lower-scoring peers. In addition, it is likely that the highest-scoring students create more opportunities for their own learning in small classes than other students.
It behooves President Obama and Congress to ponder such research results as they begin to make good on their campaign promises to fix America’s schools. It may be possible over a long horizon to close both the domestic and international achievement gaps. But, in the near term, it is not likely to be accomplished by the universalization of interventions like as class-size reduction. Meanwhile, restricting educational interventions to the lowest-scoring students will help close our domestic achievement gap but probably at the expense of failing to close the international gap between our top students’ achievement and that of the top students abroad.
Policy makers will have to struggle with thorny ethical issues to balance the needs of different students: Providing small classes for students of all ability levels, as opposed to restricting small classes to students who are in greatest educational need, will help all children achieve their potential but widen the gap among the top and bottom performers. It is an empirical question whether there is a certain mix of interventions, some focused on the lowest-achieving students and some made universally available, that produces the best overall cost-benefit ratio for a nation on political, economic, and moral grounds.
The new president and Congress come to office at a time when America has no consensual political philosophy that is mindful of both the need to elevate the top students and the need to redress past injustice in a manner that will best achieve national interests and values. As a first step, they need to be aware of this trade-off.
Stephen J. Ceci is a professor of developmental psychology at Cornell University. Spyros Konstantopoulos is an assistant professor of educational research, measurement, and evaluation at Boston College.
http://chronicle.com Section: Commentary Volume 55, Issue 21, Page A30