The simulated study on the effect strong teachers can have on students, released last week by the Center for Analysis of Longitudinal Data in Education Research, makes an excellent point about the value of excellent educators. Certainly we all agree that great teachers make great schools.
What the simulation does not do is stack up against the volumes of research showing conclusively that smaller class sizes have a dramatic impact on student performance. Research on class size has been conducted in states across the country, and from California to Wisconsin the results are the same — smaller classes mean higher student achievement.
The famous STAR Study (done by researchers with whom I studied) conducted in Tennessee in the late 1980s tracked two groups of students — one placed in smaller classes in early grades and the second in larger classes. Not only did the students in smaller classes do better in those early grades, they continued to out-perform their peers all the way through high school — even after they returned to classrooms with more students.
A little more than a decade later, the U.S. Department of Education commissioned a study of 2,561 schools across the country. That study found that after controlling for student background, the only objective factor found to correlate with student achievement was class size. It is one of the reasons the education department identifies class size reductions as one of only four evidence-based education improvements that boost student performance.
The simulated study is interesting, and perhaps it will help spur a full study of class size in North Carolina. But the research is hardly mixed. The overwhelming conclusion drawn from serious studies of class size is that class size counts.
Gary Plano is superintendent of Mercer Island Schools and a committee member of the non-profit organization Class Size Counts.