Dispelling the class size myth
As teachers’ strikes continue to spread across Illinois, union officials are pushing back against criticisms that they are not doing enough to raise student achievement. One of the most common excuses they use to explain the lack of results – apart from claiming that low-income populations have too many issues to overcome, something the Institute showed is...
As teachers’ strikes continue to spread across Illinois, union officials are pushing back against criticisms that they are not doing enough to raise student achievement. One of the most common excuses they use to explain the lack of results – apart from claiming that low-income populations have too many issues to overcome, something the Institute showed is not true in its latest report – is that class sizes are too big.
The Chicago Teacher’s Union (CTU) even authored a report on the topic, asking the city council to divert $170 million of the $351 million set aside for charter school expansion in 2012 toward reducing average class sizes from 28 to 20 students.
With CPS anticipating a budget deficit of more than $1 billion in 2013, is reducing class sizes the best way to spend money that it doesn’t have?
Admittedly, Chicago’s average class sizes are larger than many other schools in Illinois. Chicago has the 14th highest average class size across elementary grades and the fifth largest average high school class size.
This is why CTU President Karen Lewis thinks that decreasing class sizes is a good idea:
“Reducing class sizes can lead to improved teaching and learning. In a smaller classroom, a teacher has more time to get to know each student’s academic strengths and weaknesses; students receive more attention and teachers can spend more time helping students learn and working with parents.”
While some studies have shown that reducing class sizes can work if applied in a strategic manner (i.e., having more experienced, higher quality teachers teach more children and vice versa), most paint the policy as a costly mess.
Recognizing this, the CTU report relies on a study conducted by Tennessee’s Student Teacher Achievement Ratio (STAR) Project in 1999 that found that a 32 percent reduction in K-3 classes (from 24-28 students to 13-17 students) improved student achievement by about 15 percent a year. What they don’t mention in their report is telling – that reducing class sizes by as much as the CTU wants will require hiring hundreds of more teachers and spending millions of dollars on renovating and constructing new buildings.
The report also fails to mention the other peer-reviewed studies that found that reducing class sizes had little to no effect on increasing student achievement. In one study, Stanford’s Eric Hanushek compiled 276 estimates of class-size effects from 59 studies, and found that only 11 percent of them indicated positive effects on student performance. Another researcher, Caroline Hoxby, found in a Connecticut-based study that no relationship exists between class size and achievement in fourth and sixth grade.
Thankfully, some states, like Florida have already shown that imposing specific caps on class size is not cost-effective. There, the policy (which only reduced average class sizes by 3 to 5 students) cost about $20 billion to implement during its first eight years, with costs of $4 billion to $5 billion a year since.
The money put toward reducing class sizes would be much better spent paying high-quality teachers. Astudy by Eric Hanushek and Steven Rivkin estimated that replacing the worst 5 to 8 percent of teachers in the U.S. with average – not great – teachers would dramatically boost student achievement.
Implementing reforms that increase pay for high quality teachers – including paying them more to teach at low-performing schools – would do wonders for student outcomes.
So, the next time you hear someone like Karen Lewis promoting class-size reduction, remember to ask yourself this question:
Is this the best way to spend money we don’t have?