NAEP Analysis and Scaling - Overall Descriptive Statistics for Items as Defined After Scaling, Grade 8 Writing Combined National and State Main Assessment: 2002

NAEP Analysis and Scaling → Initial Activities → Classical Item Analysis → Overall Descriptive Statistics for Items as Defined After Scaling, Grade 8 Writing Combined National and State Main Assessment: 2002

NAEP Technical DocumentationOverall descriptive statistics for items as defined after scaling, grade 8 writing combined national and state main assessment: 2002
Statistic	All items
Number of scaled items	20
Multiple choice	0
Dichotomously scored constructed response	0
Polytomously scored constructed response	20
Unweighted sample size	123,000
Weighted average item score	0.54
Weighted average polyserial	0.92
Weighted alpha reliability	†
† In NAEP writing assessments, each block contains only one item—a writing prompt to which students respond with a polytomously scored constructed response; therefore, the weighted alpha reliability estimate is not meaningful. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2002 Writing Assessment.

Last updated 16 February 2009 (GF)