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NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Overall Descriptive Statistics for Item Blocks as Defined After Scaling, Age 9 Reading Long-Term Trend National Assessment, by Block: 2020
NAEP Technical DocumentationOverall Descriptive Statistics for Item Blocks as Defined After Scaling, Age 9 Reading Long-Term Trend National Assessment, by Block: 2020
| Statistic | Block R1 | Block R2 | Block R3 | Block R4 | Block R6 | Block R7 | Block R8 | Block R9 | Block R10 |
|---|---|---|---|---|---|---|---|---|---|
| The "Weighted average item score" of polytomous items is 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). Weights are applied to reflect sampling design. | |||||||||
| CR = Constructed response. Item statistics in this table are described on the page Blocks of Items. | |||||||||
| 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. | |||||||||
| Total number of scaled items | 8 | 10 | 7 | 8 | 10 | 8 | 9 | 10 | 8 |
| Number of multiple-choice items | 7 | 10 | 6 | 7 | 10 | 8 | 9 | 10 | 8 |
| Number of dichotomously scored CR items | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| Number of polytomously scored CR items | 1 | 0 | 1 | 1 | 0 | 0 | 0 | 0 | 0 |
| Unweighted sample size | 2,800 | 2,800 | 2,800 | 2,800 | 2,700 | 2,800 | 2,800 | 2,800 | 2,800 |
| Weighted average item score | .48 | .61 | .62 | .54 | .71 | .72 | .71 | .68 | .69 |
| Weighted average R biserial/polyserial | .68 | .66 | .70 | .70 | .77 | .74 | .80 | .75 | .82 |
| Weighted alpha reliability | .63 | .69 | .65 | .72 | .75 | .70 | .78 | .75 | .77 |
| Weighted proportion of students attempting last item | .76 | .92 | .88 | .83 | .94 | .95 | .92 | .91 | .97 |
Last updated 30 April 2024 (PG)