The 2006 sample design met the following objectives:
These objectives were met 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 grade-specific enrollment in the schools.
The assessment was designed to achieve a nationally representative sample of public and private school students in the fourth, eighth, and twelfth grades. Its target population included all students in public and private schools, including Bureau of Indian Education (BIE) schools and Department of Defense Dependent Elementary and Secondary Schools (DDESS), who were enrolled in fourth, eighth, and twelfth grades at the time of assessment.
|† Not applicable.
NOTE: Detail may not sum to totals due to rounding.
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2006.
Two additional NCES studies were conducted at the same time as the NAEP 2006 assessments. They were similar in nature to NAEP, were small, and already had school samples identified; therefore, NAEP avoided selecting the schools that were already selected for these studies. The first of these studies was the NAEP-related Sensitivity to Instruction Study (STI), involving 41 purposively selected public schools at grade 8, comprising 10 or 11 in each of four states. The second study was the Progress in International Reading Literacy Study (PIRLS), involving a sample of about 230 grade 4 public and private schools, selected randomly, together with 460 substitute schools. NAEP avoided the 271 original school selections for these two studies by invoking the substitute in the few cases where the initial NAEP selection was already selected for either study. NAEP avoided the 460 PIRLS substitute selections to the extent that NAEP substitutes for grade 4 were not drawn from among these 460.