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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 Civics National Assessment: 2014
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Proportion of Variance of the Group-Defining Contrasts Accounted for by the Principal Components Used in the Population-Structure Model, Grade 8 Civics National Assessment: 2014

Proportion of variance of the group-defining contrasts accounted for by the principal components used in the population-structure model, grade 8 civics national assessment: 2014
Type of contrastNumber of contrastsMeanMinimumMaximumNumber of contrasts by proportion1 of variance explained
.00 - .70.70 - .80.80 - .90.90 - .95.95 - 1.00
1 (Total Variance – Residual Variance) / Total Variance, where Total Variance consists of sampling, measurement, and other sources of error.
NOTE: SD/EL = Students with disabilities/English learners. In 2014, grades 4 and 12 were not assessed.
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2014 Civics Assessment.
All contrasts1236.90.67.99657484503186
Student questionnaire230.88.69.98133828133
Major reporting variables72.91.80.9902292219
Interactions between reporting variables247.89.67.985217611332
Teacher questionnaire372.90.84.990019711758
School questionnaire278.92.86.99007815743
SD/EL questionnaire34.88.79.950122101
Student questionnaire indices3.94.93.9500030
Last updated 30 August 2021 (ML)