The National Assessment of Educational Progress (NAEP) is the largest continuing national assessment of what America's students know and how they can do in various subject areas. Assessments are conducted periodically in mathematics, reading, science, writing, the arts, civics, economics, geography, and U.S. history.
This slideshow is based on average NAEP scores in reading and mathematics for the 4th grade. The scores were taken from the 2009 NAEP, the most recent year from which results are available.
The U.S. scored 220 in reading and 239 in math, for an average score of 229.5. Keep clicking to find out how each state fared.