NAEP Technical DocumentationProportion of scale score variance accounted for by the population-structure model, U.S. history national assessment, by subscale and grade: 2014
Grade
Number of initial conditioning contrasts2
Number of principal components2
Proportion1 of scale score variance
Democracy
Culture
Technology
World role
1 (Total Variance – Residual Variance)/Total Variance, where Total Variance consists of sampling, measurement, and other sources of error. 2 Excluding the contant term.
NOTE: 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 U.S. History Assessment.