From the National Center for Education Statistics:
The National Assessment of Educational Progress (NAEP) long-term trend assessments provide the most extended retrospective picture of student achievement in the United States. Results span four decades of student performance by 9-, 13-, and 17-year-olds in reading and mathematics.
Both 9- and 13-year-olds scored higher in reading and mathematics in 2012 than students their age in the early 1970s. Since the last administration of the assessments in 2008, only 13-year-olds made gains and did so in both reading and mathematics. Scores for 17-year-olds overall were not different from scores for their peers in the earliest and most recent assessment years. However, scores for White, Black, and Hispanic 17-years-olds were higher in 2012 than in the first assessment year.
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