Battle of the studies: Does class size matter?

There is an ongoing discussion or battle about whether class size matters in effective learning. Class size reduction theory has both supporters and skeptics. Leonie Hamson writes in the Washington Post article, 7 Class Size Myths — And the Truth

So perhaps its time to review what the research really says and what experience shows about the importance of reducing class size. Here are seven myths about class size, commonly repeated as gospel by the corporate-type reformers, juxtaposed with the facts.

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

Studies from Tennessee, Wisconsin, and states throughout the country have demonstrated that students who are assigned to smaller classes in grades K-3rd do better in every way that can be measured: they score higher on tests, receive better grades, and exhibit improved attendance.

The Institute of Education Sciences, the research arm of the U.S. Department of Education has concluded 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 1-3; 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.

A recent re-evaluation of the STAR experiment in Tennessee revealed that students who were in smaller classes in Kindergarten had higher earnings in adulthood, as well as a greater likelihood of attending college and having a 410K retirement plan. In fact, according to this study, the only two “observable” classroom factors that led to better outcomes were being placed in a small class and having an experienced teacher.

2. Myth: There is a threshold that has to be reached before class size reduction provides benefits.

Since STAR involved comparing outcomes between students in classes of 22 to 25 students and those in classes of 13 to 17, many critics have argued that classes have to be reduced to a certain level to provide benefits.

Yet Alan Krueger of Princeton University analyzed the STAR results 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.

Actually, every controlled study of the California class size reduction program –and there have been at least six so far—have shown significant gains from smaller classes.

Unlike the STAR studies, nearly all elementary schools in the state reduced class size at once –especially in grades K-2nd—so it was hard to find a control group with which to compare outcomes. Also, the state exam was new, making it difficult to compare achievement gains to past trends.

Yet given these limitations, the results were striking: even when analyzing the achievement of third graders who had the benefits of a smaller class for only one year, as compared to those who were in large classes, the gains were substantial, especially for disadvantaged students in inner-city schools.

In the five largest school districts other than Los Angeles, namely San Diego, San Francisco, Long Beach, Oakland and Fresno, researchers found that class size reduction raised the proportion of third graders who exceeded the national median by l0.5 % in math, and 8.4 % in reading, after controlling for all other factors. Even larger gains occurred in schools with high numbers of poor students, and in schools that had 100% black enrollment, lowering class size resulted in 14.7% more students exceeding the national median in math, and 18.4% more in reading.

Another researcher, Fatih Unlu, avoided some of the pitfalls encountered by other researchers who were stymied by the fact that the state tests were new and there were few students to use as a control group. In his paper, he instead analyzed the change in National Assessment of Educational Progress scores, and by using two different statistical methods, he found very substantial gains from smaller classes.

4. Myth: Class size reduction lowers the quality of teachers.

This urban legend is often repeated by the corporate-style reformers. Typical is the claim from
Mr. Snider, that lowering class size in California “had the unintended effect of creating a run on good teachers: the best teachers tended to flee to the suburbs, which were suddenly hiring and which offered better pay and working conditions…”

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

Although there has been no large scale experiment done for the middle and upper grades, as STAR did in the early grades, there are numerous studiesthat show smaller classes are correlated with achievement gains and/or lower dropout rates in the middle and upper grades as well.

One comprehensive study, done for the U.S. 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….

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

Many studies have shown that class size reduction is cost-effective because it results in higher wages later in life (see the above study, for example), and lower costs for health care and/or welfare dependency.

One re-analysis of the STAR data published in the American Journal of Public Health estimated that reducing class sizes may be more cost-effective than almost any other public health and medical intervention, with large savings in health care and almost two years of additional life for those students who were in smaller classes in the early grades….

Also, class size reduction is one of very few educational interventions that have been proven to narrow the achievement gap, with students from poor and minority backgrounds experiencing twice the gains as the average student. While many of the high-achieving charter schools, such as the Icahn charter schools in the Bronx, and those highly celebrated such as Harlem Children’s Zone, cap class sizes at 18 or less, class sizes in our inner-city public schools continue to grow.

As a recent issue brief on the achievement gap from the Educational Testing Service pointed out, schools having high numbers of minority students are more likely to feature large classes of 25 students or more, with the class size gap between high-minority schools and low-minority schools larger over time. Don’t we have a moral obligation to provide equitable opportunities to all children?

So the next time somebody with power or influence tells you that class size reduction is a waste of money, ask him what the evidence-base is for the policies he favors instead. Or ask him what class sizes were in the school his own child attends.

Many of the individuals who are driving education policy in this country, including New York City Mayor Michael Bloomberg, New York City Schools Chancellor Joel Klein and Bill Gates, sent their own children to private schools where class sizes were low and yet continue to insist that resources, equitable funding, and class size don’t matter – when all the evidence points to the contrary.

As John Dewey wrote, “What the best and wisest parent wants for his own child, that must the community want for all of its children.” If education is really the civil rights issue of our era, it is about time those people making policies for our schools begin to provide for other people’s children what they provide for their own.

There is of course, a contrary opinion.

The Center for American Progress has a report by Mathew M. Chingos, The False Promise of Class-Size Reduction

In the Executive Summary Chingos reports:

There is surprisingly little high-quality research, however, on the effects of class size on student achievement in the United States. The credible evidence that does exist is not consistent, and there are many low-quality studies

with results all over the map. The most encouraging results for CSR come from a single experiment conducted in the 1980s, which found that a large reduction in class size in the early grades increased test scores, particularly among low-income and African American students. But evaluations of large-scale CSR policies in California and Florida have yielded much less positive results, perhaps because of the need to hire so many (inexperienced and potentially less effective) new teachers.

Chingos does not believe the advocates for smaller class size have made their case.

Suzy Kihmm reports in the Washington Post article, Study: Class size doesn’t matter:

Two Harvard researchers looked at the factors that actually improve student achievement and those that don’t. In a new paper for the National Bureau of Economic Research, Will Dobbie and Roland Freyer analyzed 35 charter schools, which generally have greater flexibility in terms of school structure and strategy. They found that traditionally emphasized factors such as class size made little difference, compared with some new criteria:
We find that traditionally collected input measures — class size, per pupil expenditure, the fraction of teachers with no certification, and the fraction of teachers with an advanced degree — are not correlated with school effectiveness. In stark contrast, we show that an index of five policies suggested by over forty years of qualitative research — frequent teacher feedback, the use of data to guide instruction, high-dosage tutoring, increased instructional time, and high expectations — explains approximately 50 percent of the variation in school effectiveness.                                            http://www.washingtonpost.com/blogs/ezra-klein/post/study-class-size-doesnt-matter/2012/01/28/gIQAaiZAYQ_blog.html?hpid=z3

Catherine Rampell wrote in the 2009 New York Times article, Class Size Around the World:

Note that some of the countries with some of the world’s highest achieving student bodies — like Korea and Japan — have the biggest class sizes. Perhaps this has to do with cultural differences; societies with Confucian roots may have stricter hierarchies within the classroom, so perhaps it’s easier (or more expected) for a single teacher to manage a bigger group of students. But presumably there are other explanations, too.http://economix.blogs.nytimes.com/2009/09/11/class-size-around-the-world/

Rampell includes charts from the Organization for Economic Cooperation and Development in her article.

Something to think about.

Here is the citation:

Getting Beneath the Veil of Effective Schools: Evidence from New York City

Will Dobbie, Roland G. Fryer, Jr

NBER Working Paper No. 17632

Issued in December 2011

NBER Program(s):   ED   LS                                                                                                                                      You may purchase this paper on-line in .pdf format from SSRN.com ($5) for electronic delivery.

Dr. Wilda says this about that ©