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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 Variance Accounted For by Principal Components Used in NAEP Population-Structure Models → Proportion of Variance of the Group-Defining Contrasts Accounted for by the Principal Components Used in the Population-Structure Model, Grade 8 National Civics Assessment: 2010
NAEP Technical DocumentationProportion of variance of the group-defining contrasts accounted for by the principal components used in the population-structure model, grade 8 civics national assessment: 2010
Type of contrast Number of contrasts Mean Minimum Maximum Number of contrasts by proportion1 of variance explained
0.00 - 0.70 0.70 - 0.80 0.80 - 0.90 0.90 - 0.95 0.95 - 1.00
1 (Total Variance – Residual Variance)/Total Variance, where Total Variance consists of both sampling and measurement error variance.
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2010 Civics Assessment.
All contrasts 1457 0.90 0.66 0.99 9 72 594 496 286
Student questionnaire 226 0.88 0.66 0.99 5 42 64 79 36
Major reporting variables 63 0.92 0.79 0.99 0 1 27 12 23
Interactions between reporting variables 492 0.91 0.68 0.99 4 27 133 173 155
Teacher questionnaire 382 0.89 0.80 0.98 0 0 231 120 31
School questionnaire 257 0.91 0.85 0.99 0 0 122 98 37
SD/ELL questionnaire 37 0.88 0.77 0.97 0 2 17 14 4
Last updated 05 January 2016 (GF)
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