About the 2008 Long-Term Trend Assessment
The long-term trend results in mathematics and reading presented on this website were obtained through the cooperation of schools, teachers, and students across the nation. Because the long-term trend assessments use different questions from those used in the main assessments, and because students are sampled by age rather than by grade as in the main assessments, it is not possible to compare results from the two assessment programs. Read more about the differences between long-term trend and main NAEP assessments. See more information about the long-term trend assessment, including procedures used to collect data and the number of students who participated in the 2008 administration.
Results are presented on this website in terms of average scale scores, performance levels, and percentiles. Performance levels for the long-term trend assessment differ from the achievement levels reported with main NAEP assessment results. For more information, read descriptions of the performance levels for the long-term trend mathematics and reading assessments.
In 2004, a number of changes were
made to the long-term trend assessment to update the
assessment content and procedures while continuing to
maintain the integrity of the long-term trend. Some of the
changes included replacing questions that were based on
outdated contexts; changing some administration procedures;
and, most notably, providing accommodations for
students with disabilities and for English language learners. These revisions did not alter the knowledge and skills that are assessed by the long-term trend assessments.
To ensure that results from the revised assessment format
could be validly compared to results from earlier assessments, a special bridge study was conducted in 2004. The 2008 results can be compared to previous years because of extensive linking procedures, including the bridge study in 2004 which takes into account several changes in the assessment procedures. In the tables and figures on this website, results from 2004 are shown for both the original and revised versions of the assessments. While two sets of results are presented for 2004, comparisons between 2004 and 2008 are discussed based on the results for students assessed with the revised assessment format.