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NAEP Analysis and ScalingInitial ActivitiesClassical Item Analysis → Block-level Descriptive Statistics as Defined After Scaling, Grade 8 Geography National Assessment, by Public and Nonpublic School Sessions: 2014
NAEP Technical Documentation

Block-level Descriptive Statistics as Defined After Scaling, Grade 8 Geography National Assessment, by Public and Nonpublic School Sessions: 2014

Block-level descriptive statistics as defined after scaling, grade 8 geography national assessment, by public and nonpublic school sessions: 2014
StatisticType of school1Block G3Block G4Block G5Block G6Block G7Block G8Block G9
Number of scaled items17161616141725
Unweighted sample sizePublic2,0002,0002,0002,0002,0002,0001,900
Nonpublic240240220230230240240
Weighted average item score2Public.48.51.50.41.56.46.54
Nonpublic.55.58.60.49.65.54.60
Weighted average polyserialPublic.56.51.51.51.60.48.52
Nonpublic.56.50.49.47.62.48.51
Weighted alpha reliabilityPublic.73.70.71.72.74.67.80
Nonpublic.74.67.64.68.73.68.76
Weighted proportion of students attempting last item3Public.96.93.90.86.72.90.98
Nonpublic.96.98.95.87.81.931.00

† Not applicable.
1 Nonpublic school sample includes only private schools, including Catholic schools.
2 The "Weighted average item score" of polytomous items are standarized 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. In 2014, grades 4 and 12 were not assessed.
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2014 Geography Assessment.


Last updated 23 May 2021 (SK)