A representative sample of 122,000 eighth-graders participated in the 2011 National Assessment of Educational Progress (NAEP) science assessment, which is designed to measure students' knowledge and abilities in the areas of physical science, life science, and Earth and space sciences. This report covers the overall results, achievement level percentages and average score results, comparison of the average scores in 2009 and 2011 to other states/jurisdictions, average scores for state/jurisdiction and nation (public), results for student groups in 2011, and score gaps for student groups. In 2011, the average score of eighth-grade students in Colorado was 161. This was higher than the average score of 151 for public school students in the nation. The average score for students in Colorado in 2011 (161) was higher than their average score in 2009 (156). In 2011, the score gap between students in Colorado at the 75th percentile and students at the 25th percentile was 43 points. This performance gap was not significantly different from that of 2009 (43 points). The percentage of students in Colorado who performed at or above the NAEP "Proficient" level was 42 percent in 2011. This percentage was greater than that in 2009 (36 percent). The percentage of students in Colorado who performed at or above the NAEP "Basic" level was 75 percent in 2011. This percentage was greater than that in 2009 (70 percent). [For the main report, "The Nation's Report Card: Science 2011. National Assessment of Educational Progress at Grade 8. NCES 2012-465," see ED531894.]