Too Big High Schools: Science Videos - Science News - ScienCentral But just how large a school is too large? University of Michigan education researcher Valerie Lee set out to find the answer. She divided a national sample of about 800 public and private high schools into categories by size, and measured the learning of close to 10,000 students during four years of high school. Lee reported in the journal Educational Evaluation and Policy Analysis that regardless of the schools' resources or students' backgrounds, they learned the most at schools of 600 to 900 students. "The category '600 to 900' was where students learn the most," says Lee. "When schools got smaller than that, learning was less, and when schools got larger than that, learning was less and continued to be less as they got larger and larger." Lee also was interested in how school size affects different students. "The category '600 to 900' really popped out as the ideal category, regardless of the social composition of the high school, regardless of the kinds of students who went there." But she did find that "school size makes more difference for the learning of disadvantaged students, than it does for more advantaged students. For schools that enrolled mostly affluent and white students, school size still followed the same pattern, still peaked in schools of 600 to 900, but the differences in learning were considerably less."