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 Reading Combined National and State Assessments: 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 Reading Assessment. |
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| All contrasts | 2046 | 0.90 | 0.65 | 1.00 | 12 | 84 | 850 | 674 | 426 |
| Student questionnaire | 63 | 0.90 | 0.70 | 0.99 | 1 | 9 | 11 | 20 | 22 |
| Major reporting variables | 248 | 0.92 | 0.66 | 1.00 | 3 | 11 | 59 | 97 | 78 |
| Interactions between reporting variables | 372 | 0.90 | 0.65 | 0.98 | 7 | 25 | 99 | 173 | 68 |
| Teacher questionnaire | 301 | 0.92 | 0.75 | 0.99 | 0 | 6 | 88 | 84 | 123 |
| School questionnaire | 702 | 0.90 | 0.77 | 0.99 | 0 | 7 | 391 | 224 | 80 |
| NIES questionnaire | 323 | 0.87 | 0.70 | 0.99 | 1 | 25 | 191 | 69 | 37 |
| SD/ELL questionnaire | 37 | 0.92 | 0.80 | 1.00 | 0 | 1 | 11 | 7 | 18 |
Last updated 05 January 2016 (GF)