Small class size helps to bridge gap in achievement

Smaller classes may offer a solution to a puzzling and disturbing gap in academic achievement between white and black students, according to recent research by Diane Whitmore, an Assistant Professor in the Irving B. Harris Graduate School of Public Policy Studies who joined the faculty this quarter.

Whitmore views “the color line in academic achievement as the most pressing question in education in the next 30 years.” She and her colleague at Princeton University, professor Alan Krueger, presented their analysis of the impact of small class size in a paper included in the book Bridging the Achievement Gap.

“There was about a 1.2 standard deviation gap in test scores between black and white students in the early ’70s that was closing until the end of the ’80s, but then stagnated,” Whitmore said.

In the mid-1980s, Lamar Alexander, Tennessee governor, led an effort to determine the value of small classes with a study of over 11,000 students in 79 Tennessee public schools during the pupils’ kindergarten- through third-grade years. “Part of the problem with normal studies on class sizes is that there are all sorts of unobservable factors going on. The parents may have demanded it, for example,” Whitmore explained. In the Tennessee experiment, students within a school were randomly assigned to small (15 students) or regular (22 students) class sizes. Once students reached fourth grade, they all returned to regular-size classes.

Whitmore and Krueger tracked the SAT and ACT scores of the Tennessee students when they graduated from high school and established that the students enrolled in small classes during their first four years of education had higher average test scores than students enrolled in regular-size classes during those early grades.

Whitmore and Krueger’s most significant finding was that black students tended to advance further up the distribution of test scores than did white students, while they were enrolled in small classes and later when they returned to regular-size classes.

“We found that black students in small classes from K to 3 had a dramatically increased probability of subsequently taking the ACT or SAT,” Whitmore said. “The black-white gap is reduced by 60 percent, which is huge.” In addition, Whitmore noted, reducing that gap “appears to be a contributing factor in income, health, crime and other outcomes.

“Though it seems intuitive that smaller classes are naturally better, the conventional wisdom among economists and educators has been that more resources, including small classes, don’t really matter and don’t help test scores.” Whitmore and Krueger believe their research offers evidence that small classes, though they add cost to school budgets, not only matter, but they specifically address the black-white achievement gap.

Whitmore will continue this research at the Harris School, where she teaches education policy. “We need to understand why black students are helped more by class size, and more broadly, how different racial, gender and socioeconomic profiles affect students while they are in that class and in the long run,” she said.

Between her undergraduate work at Wellesley College in economics and religion and her graduate studies at Princeton University where she earned her Ph.D., Whitmore spent two years in Washington at the Council of Economic Advisers, which then was headed by Nobel laureate Joseph Stiglitz.

“My research interest always has been primarily focused on low-income children, and my time in Washington made me realize just how big an impact government policies can have on the lives of kids,” Whitmore said.