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Statistic | Item type | Block R1 | Block R2 | Block R3 | Block R4 | Block R5 | Block R6 | Block R7 | Block R8 | Block R9 | Block R10 |
---|---|---|---|---|---|---|---|---|---|---|---|
Number of scaled items | Total | 11 | 8 | 10 | 10 | 10 | 10 | 10 | 10 | 9 | 8 |
Multiple choice | 8 | 5 | 7 | 7 | 6 | 7 | 7 | 6 | 5 | 6 | |
Dichotomously scored constructed-response | 1 | 1 | 0 | 0 | 1 | 0 | 1 | 0 | 1 | 1 | |
Polytomously scored constructed-response | 2 | 2 | 3 | 3 | 3 | 3 | 2 | 4 | 3 | 1 | |
Unweighted sample size | † | 29,300 | 29,800 | 29,100 | 29,100 | 29,100 | 29,300 | 29,600 | 29,300 | 29,100 | 29,100 |
Weighted average item score1 | † | .65 | .59 | .53 | .53 | .44 | .46 | .51 | .47 | .48 | .52 |
Weighted average polyserial | † | .68 | .70 | .73 | .71 | .68 | .66 | .64 | .70 | .64 | .67 |
Weighted alpha reliability | † | .77 | .71 | .79 | .76 | .76 | .75 | .72 | .78 | .70 | .63 |
Weighted proportion of students attempting last item2 | † | .91 | .87 | .86 | .89 | .88 | .85 | .85 | .84 | .87 | .93 |
† Not applicable. 1 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. 2 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), 2017 Reading Assessment. |