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NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Overall Descriptive Statistics for Item Blocks as Defined After Scaling, Grade 8 Mathematics Combined National and State Assessment, by Block: 2019
NAEP Technical DocumentationOverall Descriptive Statistics for Item Blocks as Defined After Scaling, Grade 8 Mathematics Combined National and State Assessment, by Block: 2019
| Statistic | Block M1 | Block M2 | Block M3 | Block M4 | Block M5 | Block M6 | Block M7 | Block M8 | Block M9 | Block M10 | Block M11 | Block M12 | Block M13 | Block M14 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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), 2019 Mathematics Assessment. | ||||||||||||||
| Total number of scaled items | 15 | 15 | 15 | 19 | 20 | 20 | 21 | 14 | 17 | 20 | 15 | 16 | 18 | 16 |
| Number of multiple-choice items | 4 | 3 | 4 | 15 | 16 | 16 | 17 | 1 | 6 | 16 | 5 | 5 | 10 | 6 |
| Number of dichotomously scored CR items | 8 | 5 | 5 | 1 | 1 | 1 | 4 | 8 | 6 | 1 | 6 | 5 | 3 | 7 |
| Number of polytomously scored CR items | 3 | 7 | 6 | 3 | 3 | 3 | 0 | 5 | 5 | 3 | 4 | 6 | 5 | 3 |
| Unweighted sample size | 20,400 | 20,400 | 20,600 | 20,800 | 20,400 | 20,100 | 20,500 | 22,000 | 22,400 | 22,500 | 20,300 | 20,300 | 21,900 | 21,900 |
| Weighted average item score | .57 | .43 | .56 | .42 | .48 | .46 | .53 | .34 | .42 | .53 | .59 | .55 | .48 | .51 |
| Weighted average R biserial/polyserial | .66 | .66 | .63 | .63 | .60 | .58 | .61 | .70 | .68 | .64 | .62 | .68 | .68 | .64 |
| Weighted alpha reliability | .75 | .80 | .77 | .84 | .82 | .80 | .83 | .80 | .82 | .86 | .74 | .80 | .84 | .79 |
| Weighted proportion of students attempting last item | .91 | .80 | .96 | .82 | .86 | .77 | .89 | .84 | .81 | .82 | .95 | .96 | .85 | .94 |
Last updated 05 October 2023 (SK)