Nearly nine in 10 parents in the United States believe that their child is performing at or above grade level in reading and math. Many, if not most, of them are wrong. Actual proficiency rates among eighth graders are 30 percent in reading and 28 percent in math, as measured by the National Assessment of Educational Progress, or N.A.E.P. The gap between grades and test scores is particularly pronounced in schools serving higher proportions of low-income students, according to a 2023 study.