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NAEP Analysis and Scaling → Estimation of Population and Student Group Distributions → Examining the Population-Structure Models Used in NAEP → Proportion of Scale Score Variance Accounted for by the Population-Structure Models → Proportion of Scale Score Variance Accounted for by the Population-Structure Models, Reading Combined National and State Main Assessment, by Subscale and Grade: 2005
NAEP Technical DocumentationProportion of scale score variance accounted for by the population-structure models, reading combined national and state main assessment, by subscale and grade: 2005
Grade Number of initial conditioning contrasts2 Number of principal components2 Proportion1 of scale score variance
Literary Information Task
4 3,244 559 0.42 0.45
8 3,399 519 0.46 0.50 0.52
12 2,420 333 0.58 0.55 0.54
† Not applicable; category does not exist in this grade and year.
1(Total Variance – Residual Variance)/Total Variance, where Total Variance consists of both sampling and measurement error variance.
2Excluding the constant term.
NOTE: There were no state assessments for grade 12 in 2005.
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2005 Reading Assessment.

Last updated 14 May 2009 (RF)

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