Authors: James S. Braswell, Mary C. Daane, and Wendy S. Grigg
Average scores were higher in 2003 than in all the previous assessment years at both grades 4 and 8. (Differences are discussed in the report only if they were found to be statistically significant.)
* Significantly different from 2003.
Average test scores have a standard errora range of up to a few points above or below the scoredue to sampling error and measurement error. Statistical tests are used to determine whether the differences between average scores are significant; therefore, not all apparent differences may be found to be statistically significant. All the differences discussed in this report were tested for statistical significance at the .05 level.
Beginning in 2002, the NAEP national sample was obtained by aggregating the samples from each state, rather than by obtaining an independently selected national sample. As a consequence, the size of the national sample increased, and smaller differences between years or between types of students were found to be statistically significant than would have been detected in previous assessments. In keeping with past practice, all statistically significant differences are indicated in the current report.
The results presented in the figures and tables throughout this report distinguish between two different reporting samples that reflect a change in administration procedures beginning in 1996. This change involved permitting students with disabilities or limited-English-proficient students to use certain accommodations (e.g, extended time, small group testing). Comparisons between results from 2003 and those from assessment years in which both types of administration procedures were used (1996 and 2000) are discussed based on the results when accommodations were permitted, although significant differences in results when accommodations were not permitted may be noted in the figures and tables.