About the NAEP Long-Term Trend Assessment
The National Assessment of Educational Progress (NAEP) has monitored student performance since the early 1970s through its long-term trend (LTT) assessments. Results from the 2020 LTT assessments in reading and mathematics are based on nationally representative samples of 9- and 13-year-olds. Since its beginning in 1969, the primary mission of NAEP has been to measure academic progress by regularly administering various subject-area assessments to nationally representative samples of students. The existence of two national assessment programs—LTT and main NAEP—makes it possible to meet two major objectives: (1) to measure students' educational progress over a long period of time (LTT), and (2) to measure students' knowledge and skills based on the most current curricula and standards (main NAEP). It should be noted that results from the LTT assessments cannot be directly compared to those from the main NAEP assessments because the LTT assessments use different questions and because students are sampled by age rather than by grade. Learn more about the differences between the LTT and main NAEP assessments.
Several changes were made to the LTT assessment in 2004 to align it with current assessment practices and policies applicable to the main NAEP assessments. A bridge study was conducted to ensure that the trend line could be continued over time. The 2004 bridge study involves administering two assessments: one that replicates the assessment given in the 1999 and prior assessments (a bridge assessment or the original assessment format), and one that represents the new design (a modified assessment or the revised assessment format). Results for 1971–99 presented in this report are from the original assessment format, and results for 2004–20 are from the revised assessment format. In addition, results for both the original and revised assessment formats are presented for the 2004 LTT assessment. Read more information about the two assessment formats and changes made to the LTT assessment.
NAEP Long-Term Trend Survey Questionnaires
Students participating in the NAEP long-term trend assessments in reading and mathematics also responded to a short survey questionnaire. NAEP survey questionnaire responses provide additional information for understanding NAEP performance results. Although comparisons in students' performance are made based on student characteristics and educational experiences, these results cannot be used to establish a cause-and-effect relationship between the characteristics or experiences and student achievement. NAEP is not designed to identify the causes of performance differences. Therefore, results must be interpreted with caution. There are many factors that may influence average student achievement, including local educational policies and practices, the quality of teachers, available resources, and the demographic characteristics of the student body. Such factors may change over time and vary among student groups. See more about NAEP survey questionnaires.