The smaller classes performed substantially better by the end of second grade in test scores, grades, and fewer disciplinary referrals.The finding that small class sizes most benefit poor and minority students isn't surprising. Students who are less likely to succeed in school due to socioeconomic factors are more likely to benefit from increased academic and emotional attention from teachers than students who have stronger economic and educational support systems in their homes and communities.
The gains lasted. The students that had been assigned to smaller classes were more likely to graduate in four years, more likely to go to college, and more likely to get a degree in a STEM field. The positive effect was twice as large for poor and minority students, and thus narrowed the achievement gap.
[Alan] Krueger noted, as have many others, that class size reduction most benefits minority and disadvantaged students, and would be expected to narrow the racial achievement gap by about one-third. He also estimated that the economic gains of smaller classes in the early grades outweighed the costs two to one.Class size in upper grades haven't been studied as closely as in the lower grades, but indications are that smaller classes lead to short term and long term gains there as well.
[The researchers examined] data in 28 states that had implemented finance reforms between 1970 and 2010. In addition to measuring short-term outcomes, they followed up on long-term outcomes in students’ lives. The results were significant and meaningful. A 20% "increase in per-pupil spending each year for all 12 years of public school leads to 0.9 more completed years of education, 25 percent higher earnings, and a 20 percentage-point reduction in the annual incidence of adult poverty." The gains were achieved primarily by lower student-to-teacher ratios, increases in teacher salaries, and longer school years. Gains were strongest for economically deprived children and were strong enough to eliminate from two-thirds to all of the adult outcome gaps between those raised in poor and non-poor families.Other studies by other researchers have found less correlation between class size, money and achievement than the studies emphasized in these two reports, though the report says those studies tend to lump together good and bad data as well as good and bad studies, which muddies their results. But even the class size/money nay-sayers don't deny that class size and money have a positive effect. They just say it's minimal, not enough to justify the expense.