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​​What Are the Differences Between Long-Term Trend NAEP and Main NAEP?

Although long-term trend and main NAEP both assess mathematics and reading, there are several differences, particularly in the content assessed, how often the assessment is administered, and how the results are reported. These and other differences mean that results from long-term trend and main NAEP cannot be compared directly.

Learn more about the long-term trend assessment, and the main NAEP national, state, and urban district assessments.

Long-Term Trend AssessmentMain NAEP Assessment
OriginReading series began in 1971. Mathematics series began in 1973.Reading series began in 1992. Mathematics series began in 1990.
FrequencySince 2004, typically long-term trend NAEP has measured student performance in mathematics and reading every four years.
Main NAEP assessments measure student performance in mathematics and reading every two years.
Content Assessed Long-term trend NAEP has remained relatively unchanged since 1990. In the 1970s and '80s, the assessments changed to reflect changes in curriculum in the nation's schools. Continuity of assessment content was sufficient not to require a break in trends.

Mathematics focuses on numbers and numeration, variables and relationships, shape and size and position, measurement, and probability and statistics. Basic skills and recall of definitions are assessed.

Reading features short narrative, expository, or document passages, and focuses on locating specific information, making inferences, and identifying the main idea of a passage. On average, passages are shorter in long-term trend reading than in main NAEP reading.
Main NAEP assessments change about every decade to reflect changes in curriculum in the nation’s schools; new frameworks reflect these changes.

Continuity of assessment content was sufficient not to require a break in trends, except in grade 12 mathematics in 2005.

Mathematics focuses on numbers, measurement, geometry, probability and statistics, and algebra. In addition to basic skills and recall of definitions, students are assessed on problem solving and reasoning in all topic areas.

Reading features fiction, literary nonfiction, poetry, exposition, document, and procedural texts or pairs of texts, and focuses on identifying explicitly stated information, making complex inferences about themes, and comparing multiple texts on a variety of dimensions.
Question FormatsStudents respond to questions in multiple-choice format; there are also a few short answer questions (scored on a two-point scale). In reading, there are also a few questions requiring an extended answer (usually scored on a five-point scale).Students respond to questions of several possible types: multiple choice, short answer, and extended answer. Constructed-response questions may be scored as correct or incorrect, or they may be scored on a multi-level scale that awards partial credit.
Students SampledStudents are selected by age (9, 13, and 17) to represent the nation and to provide results for student groups such as Black, Hispanic, White, and sometimes others, by gender, family income, school location, and school type (public or private).

Students with disabilities (SD) and English learner (EL) students are included using the same participation guidelines and with the same accommodations (as needed) in main NAEP.

Since 2004, accommodations have been provided to enable participation of more SD and EL students.
Students are selected by grade (4, 8, and 12). Students represent the nation and provide results for student groups such as Black, Hispanic, White, and sometimes others, by gender, family income, and school location and school type.

In some assessments, samples are chosen to report on states or selected large urban districts and as a result, more students must participate.

The inclusion and accommodation treatment is the same for main and for long-term trend assessments.
Administration Long-term trend is assessed every four years, throughout the school year: in October through December for 13-year-olds, January through March for 9-year-olds, and March through May for 17-year-olds. See the schedule for all assessments (long-term trend as well as main NAEP).

Test booklets contain three 15-minute blocks of questions, plus one section of student questions concerning academic experiences and demographics.

There are no ancillary materials, such as calculators or manipulatives, provided.
Main NAEP mathematics and reading are assessed every two years (the odd-numbered years) at grades 4, 8, and 12. The administration takes place from late January through early March.

Test booklets contain two 25-minute blocks, plus student questions concerning academic experiences and demographics.

There may be ancillary materials provided with the test booklets.
Results Reported National-level performance and how it has changed since the 1970s is reported using scores on a 0-500 scale. Long-term trend also reports descriptive performance levels (150, 200, 250, 300, and 350) that have the same meaning across the three age levels. There are no NAEP achievement levels to correspond with those used in main NAEP.

Student performance results are reported mainly in the context of questionnaires given to students. Starting with the 2022 and 2023 administrations, questionnaires were also given to school administrators.
Main NAEP has been reported since the 1990s for the nation and participating states and other jurisdictions, and since 2002 for selected urban districts. Performance and how it has changed over the past several years is reported using scale scores and NAEP achievement levels. Scores are reported using either a 0-300 or 0-500 scale, depending on the subject. The NAEP achievement levels reported are NAEP Basic, NAEP Proficient, and NAEP Advanced.

Student performance results are reported in the context of the questionnaires given to the students' teachers and principals.

Last updated 01 February 2024 (FW)