Interpreting NAEP ResultsResults are EstimatesThe average scores and percentages presented on this website are estimates because they are based on representative samples of students rather than on the entire population of students. Moreover, the collection of subject-area questions used at each grade level is but a sample of the many questions that could have been asked that measure the NAEP subject frameworks. This information comes from the NAEP achievement levels, which are intended to measure how well students' actual achievement matches each of the achievement levels. The standard errors for the estimated scale scores and percentages in the figures and tables presented on this website are available through the NAEP Data Explorer. The NAEP Achievement LevelsNAEP assessment results provide information about what students know and can do. Additionally, NAEP provides information about what students should know and be able to do. This information comes from the NAEP achievement levels, which are intended to measure how well students' actual achievement matches the achievement desired of them in different subjects assessed by NAEP. The National Assessment Governing Board, as directed by the NAEP legislation, has been developing achievement levels for NAEP since 1990. A broadly representative panel of teachers, education specialists, and members of the general public help define and review achievement levels. As provided by law, the Commissioner of Education Statistics has determined that the achievement levels are to be used on a trial basis and should be interpreted and used with caution. However, both the Acting Commissioner and the Board believe these performance standards are useful for understanding trends in student achievement. Statistical SignificanceThe differences between scale scores and between percentages discussed in the results on this website take into account the standard errors associated with the estimates. Comparisons are based on statistical tests that consider both the magnitude of the difference between the group average scores or percentages and the stand errors of those statistics. Throughout the results, differences between scores or between percentages are discussed only when they are significant from a statistical perspective. All differences reported are significant at the .05 level with appropriate adjustments for multiple comparisons. The term significant is not intended to imply a judgment about the absolute magnitude of the educational relevance of the differences. It is intended to identify statistically dependable population differences to help inform dialogue among policy makers, educators, and the public. Cautions in InterpretationsUsers of this website are cautioned against interpreting NAEP results in a causal sense. Inferences related to subgroup performance or to the effectiveness of public and nonpublic schools, for example, should take into consideration the many socioeconomic and educational factors that may also impact performance.
|
