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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 12 Writing National Assessment: 2011
| 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. NOTE: NIES = National Indian Education Study; SD/ELL = Students with disabilities/English language learners. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2011 Writing Assessment. |
|||||||||
| All contrasts | 943 | 0.90 | 0.60 | 0.99 | 13 | 41 | 331 | 379 | 179 |
| Student questionnaire | 377 | 0.91 | 0.70 | 0.99 | 1 | 6 | 146 | 139 | 85 |
| Major reporting variables | 65 | 0.92 | 0.78 | 0.99 | 0 | 1 | 23 | 16 | 25 |
| Interactions between reporting variables | 296 | 0.89 | 0.60 | 0.98 | 12 | 18 | 74 | 147 | 45 |
| School questionnaire | 174 | 0.89 | 0.75 | 0.99 | 0 | 7 | 85 | 67 | 15 |
| SD/ELL questionnaire | 31 | 0.89 | 0.72 | 0.99 | 0 | 9 | 3 | 10 | 9 |
Last updated 05 January 2016 (GF)
