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NAEP Analysis and ScalingInitial ActivitiesClassical Item Analysis → Overall Descriptive Statistics for Item Blocks as Defined After Scaling, Grade 4 Mathematics Combined National and State Assessment, by Block and Item Type: 2015

NAEP Technical DocumentationOverall Descriptive Statistics for Item Blocks as Defined After Scaling, Grade 4 Mathematics Combined National and State Assessment, by Block and Item Type: 2015

Overall descriptive statistics for item blocks as defined after scaling, grade 4 mathematics combined national and state assessment, by block and item type: 2015
StatisticItem typeBlock M3Block M4Block M5Block M6Block M7Block M8Block M9Block M10Block M11Block M12
Number of scaled itemsTotal15151515161515151613
Multiple choice11111010111110111010
Dichotomously scored constructed-response2131232010
Polytomously scored constructed-response2324313453
Unweighted sample size27,700
27,600
27,500
27,700
28,900
28,800
27,500
27,400
27,500
29,000
Weighted average item score1.56.51.63.52.57.60.56.55.54.59
Weighted average polyserial.60.60.64.57.63.63.62.58.54.64
Weighted alpha reliability.73.75.79.72.79.77.76.70.69.75
Weighted proportion of students attempting last item2.92.89.88.90.75.87.92.96.93.96
† 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.
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 Mathematics Assessment.


Last updated 05 November 2021 (ML)