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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, Age 9 Reading Long-Term Trend National Assessment, by Type of Contrast: 2020
NAEP Technical DocumentationProportion of Variance of the Group-Defining Contrasts Accounted for by the Principal Components Used in the Population-Structure Model, Age 9 Reading Long-Term Trend National Assessment, by Type of Contrast: 2020
| Type of contrast | Number of contrasts | Mean | Minimum | Maximum | Number of contrasts by proportion of variance explained | ||||
|---|---|---|---|---|---|---|---|---|---|
| .00 - .70 | .70 - .80 | .80 - .90 | .90 - .95 | .95 - 1.00 | |||||
| (Total Variance – Residual Variance) / Total Variance, where Total Variance includes variance accounted and unaccounted for by the variables in the population-structure model. | |||||||||
| SD/EL = Students with disabilities/English learners. | |||||||||
| U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2020 Reading Long-Term Trend Assessment. | |||||||||
| All contrasts | 409 | .90 | .68 | .99 | 3 | 27 | 132 | 171 | 76 |
| Student questionnaire | 48 | .90 | .70 | .99 | 1 | 5 | 12 | 17 | 13 |
| Major reporting variables | 91 | .93 | .70 | .99 | 0 | 3 | 22 | 27 | 39 |
| Interactions between reporting variables | 236 | .89 | .68 | .97 | 2 | 18 | 86 | 116 | 14 |
| SD/EL questionnaire | 34 | .91 | .79 | .99 | 0 | 1 | 12 | 11 | 10 |
Last updated 08 May 2024 (SK)