Thursday, February 27, 2014

Class Size Matters: Yes or No?

I have to admit to not keeping up with research on class size in recent years.  A decade ago or so, I was under the impression that social science had reached a consensus that teacher quality mattered more than class size and that, with a high quality teacher, class size did not matter much at all. The only caveat, I thought, was that at-risk students did see some benefit from class-size reduction, even if others did not.  Leonie Haimson, Class Size Matters' Executive Director, offers a strong retort.  Below is a summary of her rebuttal of the 7 myths about class size reduction.  

1. Myth: Class size is an unproven or ineffective reform.

She points to the conclusion of the Institute of Education Sciences at the United States Department of Education that

class size reduction is one of only four, evidence-based reforms that have been proven to increase student achievement through rigorous, randomized experiments -- the "gold standard" of research. (The other three reforms are one-on-one tutoring by qualified tutors for at-risk readers in grades first through third; life-skills training for junior high students, and instruction for early readers in phonics -- and not one of the policies that the corporate reformers are pushing. )

2. Myth: There is a threshold that has to be reached before class size reduction provides benefits.
The most comprehensive study of classroom size was in Tennessee. A recent reanalysis of the data in that study found that

for the control group of students who were in the "larger" classes and found that within this range, the smaller the class, the better the outcome.

Indeed, esteemed researchers such as Peter Blatchford have found that there is no particular threshold that must be reached before students receive benefits from smaller classes, and any reduction in class size increases the probability that they will be on-task and positively engaged in learning.

3. Myth: Large scale programs such as class size reduction in California didn't work.

She indicates that control groups in California were hard to find because the entire state reduced class size, but every controlled study of California did find significant gains for students in smaller classes.

4. Myth: Class size reduction lowers the quality of teachers.
The fear is the demand to lower class size would just drive more of the better teachers out of urban schools to suburban schools. There were some anecdotal reports of this when California first reduced class size, but after the initial period “teacher migration rates fell dramatically to much lower levels than before, and most sharply in schools with large numbers of poor students. In fact, for the first time, teacher migration rates began to converge in all schools, rich and poor.” The important fact appeared to be that by improving teaching conditions in urban schools teachers were less apt to leave.

 5. Myth: Class size matters, but only in the early grades.

One comprehensive report, done for the United States Department of Education, analyzed the achievement levels of students in 2,561 schools across the country. After controlling for student background, the only objective factor found to be positively correlated with student performance was smaller classes, not school size or teacher qualifications, nor any other variable that the researchers could identify. Moreover, student achievement was even more strongly linked to class size reduction in the upper grades than the lower grades.

Two recent studies that show that class size matters, even in college.

6. Other reforms work better to narrow the achievement gap.

Instead, researchers such as David Grissmer of RAND have proposed that the reductions in class size that took place nationally in the 1970s and 1980s might account for part or most of the substantial test score gains among poor and minority students -- and the narrowing of the achievement gap -- that took place over the this period. Why? Students from disadvantaged groups experience two to three times the average gains from smaller classes than middle class white students.

7. Myth: Even if class size matters, it's just too expensive.

While there may be an upfront cost, there are lifetime savings through employment, juvenile justice, health care etc. She also emphasizes that we are wasting billions of dollars on unproven reforms. Those funds could be spent on class size.

Haimson's full article is here.  It does a good job of putting forward a comprehensive rebuttal, but it is not a comprehensive review of the literature, pro and con.  I would welcome a guest post or comments from anyone who knows of an up-to-date comprehensive literature review on the topic.

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