NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Overall Descriptive Statistics for Items as Defined After Scaling, Grade 8 Writing National Assessment, By Block: 2011
| Statistic | Item type | Block W |
|---|---|---|
| † Not applicable. NOTE: The "weighted average item score" of polytomous items are standardized to have a scale of 0 to 1 so they are comparable to dichotomously scored items. The "weighted proportion of students attempting last item" is equal to 1 (percent not responding to last item /100). Item statistics in this table are described on the page Blocks of Items. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2011 Writing Assessment. |
||
| Number of scaled items | Total | 22 |
| Multiple choice | 0 | |
| Dichtomously scored constructed response | 0 | |
| Polytomously scored constructed response | 22 | |
| Unweighted sample size | † | 24,100 |
| Weighted average item score | † | .48 |
| Weighted average polyserial | † | .94 |
| Weighted alpha reliability | † | † |
| Weighted proportion of students attempting last item | † | † |
Last updated 05 January 2016 (GF)