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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 Mathematics Long-Term Trend National Assessment, by Block: 2020
NAEP Technical DocumentationOverall Descriptive Statistics for Item Blocks as Defined After Scaling, Age 9 Mathematics Long-Term Trend National Assessment, by Block: 2020
| Statistic | Block M1 | Block M2 | Block M3 | Block M4 | Block M5 | Block M6 |
|---|---|---|---|---|---|---|
| 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 Mathematics Long-Term Trend Assessment. | ||||||
| Total number of scaled items | 24 | 23 | 22 | 24 | 21 | 20 |
| Number of multiple-choice items | 16 | 18 | 17 | 15 | 17 | 14 |
| Number of dichotomously scored CR items | 8 | 5 | 5 | 9 | 4 | 6 |
| Number of polytomously scored CR items | 0 | 0 | 0 | 0 | 0 | 0 |
| Unweighted sample size | 4,100 | 4,200 | 4,300 | 4,300 | 4,100 | 4,100 |
| Weighted average item score | .62 | .65 | .66 | .69 | .66 | .62 |
| Weighted average R biserial/polyserial | .64 | .65 | .62 | .69 | .67 | .61 |
| Weighted alpha reliability | .89 | .86 | .85 | .89 | .88 | .81 |
| Weighted proportion of students attempting last item | .71 | .73 | .82 | .74 | .78 | .80 |
Last updated 30 April 2024 (PG)