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Table of Contents | Search Technical Documentation | References
NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Block-Level Descriptive Statistics as Defined After Scaling, Grade 4 Science Combined National and State Assessment, by Block and School Type: 2015
NAEP Technical DocumentationBlock-Level Descriptive Statistics as Defined After Scaling, Grade 4 Science Combined National and State Assessment, by Block and School Type: 2015
| Statistic | Type of school1 | Block S3 | Block S4 | Block S5 | Block S6 | Block S7 | Block S8 | Block S9 | Block S10 | Block S11 |
|---|---|---|---|---|---|---|---|---|---|---|
| Number of scaled items | † | 17 | 14 | 16 | 16 | 15 | 15 | 16 | 17 | 14 |
| Unweighted sample size | Public | 26,000 | 25,000 | 25,000 | 25,000 | 24,000 | 24,000 | 24,000 | 24,000 | 24,000 |
| Nonpublic | 600 | 600 | 600 | 500 | 600 | 600 | 600 | 600 | 500 | |
| Weighted average item score2 | Public | .47 | .57 | .40 | .56 | .68 | .46 | .55 | .51 | .65 |
| Nonpublic | .53 | .64 | .45 | .63 | .72 | .52 | .60 | .55 | .70 | |
| Weighted average polyserial | Public | .50 | .58 | .51 | .55 | .64 | .49 | .47 | .48 | .65 |
| Nonpublic | .51 | .53 | .50 | .53 | .58 | .51 | .48 | .49 | .63 | |
| Weighted alpha reliability | Public | .72 | .74 | .70 | .75 | .70 | .68 | .67 | .71 | .70 |
| Nonpublic | .72 | .65 | .68 | .71 | .61 | .66 | .63 | .70 | .66 | |
| Weighted proportion of students attempting last item3 | Public | .68 | .82 | .65 | .72 | .96 | .63 | .80 | .71 | .97 |
| Nonpublic | .83 | .94 | .78 | .85 | .99 | .75 | .90 | .83 | .99 | |
| † Not applicable. 1 Nonpublic school sample includes only private schools, including Catholic schools. BIE and DoDEA schools are not included in either the public or nonpublic category. 2 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. 3 The "Weighted proportion of students attempting last item" is equal to 1 – (Percent not responding to last item / 100). NOTE: 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), 2015 Science Assessment. | ||||||||||
Last updated 09 November 2021 (ML)