Subsequent research on the effects of class size reduction has linked small class sizes with a variety of cognitive and non-cognitive benefits for students and teachers, both short and long-term, especially when class sizes are reduced in the early grades. Its benefits are particularly pronounced for lower-income students and children of color, who experience two to three times the gains from smaller classes, leading CSR to be one of only a few education reforms proven to reduce the achievement gap. Smaller classes have also been found to have a positive impact on school climate, student socio-emotional growth, safety and suspension rates, parent engagement, and teacher attrition, especially in schools with large numbers of disadvantaged children.