The 2008 arts assessment sample design provided a nationally representative sample for operational assessments in music and visual arts at grade 8.
This was accomplished by designing separate sample components for public and private schools. The selected samples were based on a three-stage sample design:
The samples of schools were selected with probability proportional to a measure of size based on the estimated eighth-grade enrollment in the schools.
The assessment was designed to achieve a nationally representative sample of public and private school students in the eighth grade. Its target population included all students in public and private schools, including Bureau of Indian Education (BIE) schools and Department of Defense Domestic Dependent Elementary and Secondary Schools (DDESS), who were enrolled in the eighth grade at the time of assessment.
The table below shows the target student sample sizes for each sample.
|School type||Arts assessment|
|SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2008 Arts Assessment.|
These targets represent completed assessments. To get the overall sample sizes, these targets were adjusted upwards to allow for expected losses from absent, refusing, and/or ineligible schools and students (so that the completed assessment targets would be met). The corresponding overall students sample sizes are contained in the Student Participation, Exclusion, and Accommodation Rates page.
Two additional NCES assessments were conducted at the same time as the NAEP 2008 arts assessment: the long-term trend (LTT) and the field test (FT) assessments. To reduce the burden on any particular school, efforts were made to minimize the overlap of the arts sample schools with the schools already selected for the LTT and FT sample. This was accomplished by applying the Keyfitz procedure in which conditional probabilities of selection were computed and used in the school sample selection process. In addition, schools that still happened to be selected for the eighth-grade FT and arts sample were dropped from the eighth-grade FT sample. This occurred for 14 eighth-grade FT sample schools.