Have Income-Based Achievement Gaps Widened or Narrowed?

Since 1990, U.S. policymakers have worked to close gaps in academic achievement by income and race (e.g. with school finance reform and school accountability systems) even as rising income inequality and income-based residential segregation have threatened to widen them. Using estimates of the mean and variance in household income for sampled schools, we reconstruct the student-level relationship between achievement and household income in the National Assessment of Educational Progress (NAEP) from 1990 to 2015. We find that achievement at all levels of parental income rose substantially in 4th and 8th grade. In contrast to Reardon (2011), we find that achievement gaps narrowed substantially in 4th grade reading and math and in 8th grade math, while the gaps remained stable in 8th grade reading. As a robustness check, we used the March Current Population survey to impute income for dependent children by race, mother's education, urbanicity and state and then calculated mean achievement for those same groups in the NAEP. Again, we found gaps in achievement narrowing between groups with high and low predicted mean household incomes. Our results challenge the prevailing understanding that income-based achievement gaps have widened in the United States over the last 30 years