NAEP Technical DocumentationStudent Selection for the 2008 Public School Long-Term Trend (LTT) Assessment

Within each sampled school, a sample of students was selected from a listing of the age-eligible students such that every student had an equal chance of selection. The student lists were submitted in multiple ways. E-Filing is an electronic submission system. Excel files are submitted for sampled schools by school coordinators or NAEP State Coordinators. Files can be submitted for one school at a time or for an entire jurisdiction at once. This method allows schools to easily submit student demographic data electronically with the student lists, easing burden on NAEP field supervisors and school coordinators. Schools that are unable to submit their student lists using the E-Filing system provide hardcopy lists via the student listing form to NAEP field supervisors.

In year-round, multi-track schools, students who are not scheduled to be in school on the assessment day are removed from the student lists prior to sampling. Student base weights were adjusted to account for these students.

The sampling process was the same regardless of list submission type. The sampling process was systematic (e.g., if the sampling rate was 1/2, a random starting point of one or two was chosen, and every other student on the list was selected). For E-Filed schools only, where demographic data is submitted for every student on the frame, students are sorted by sex and race before the sample is selected to implicitly stratify the sample.

Some students enrolled in the school after the sample was selected. In such cases, new enrollees were sampled at the same rate as the students on the original list.

Students were randomly assigned to a reading, mathematics, or mathematics pilot assessment with 15/31, 15/31, and 1/31 probability, respectively. The booklet assignment was implemented by spiraling: the booklets assigned to sampled students were provided from booklet packets which had, on average, the correct proportion of each of the relevant assessments in a randomized order.

Some of the students who were English language learners (ELL) or students with disabilities (SD) were excluded from the assessment because they could not be assessed with the accomodations NAEP provides. Excluded students were removed from the sample.

The student sample consisted of all age-eligible students in the school if the school had 62 or fewer students, or a sample of 62 students selected without replacement, if the school had 63 or more students.

Last updated 15 March 2011 (GF)

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