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​​NAEP Technical DocumentationProportion of Scale Score Variance Accounted for by the Population-Structure Model, Science National Assessment, by Scale and Grade: 2019

Proportion of scale score variance accounted for by the population-structure model, science DBA national assessment, by scale and grade: 2019
Grade Number of initial conditioning contrasts Number of principal components Proportion of scale score variance
Univariate scale Physical science Earth and space sciences Life science
(Total Variance – Residual Variance) / Total Variance, where Total Variance includes variance accounted and unaccounted for by the variables in the population-structure model.
Excluding the constant term.
DBA = Digitally based assessment.
U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2019 Science Assessment.
4 1986 617 .65 .65 .68 .62
8 2215 645 .66 .64 .65 .67
12 2097 611 .70 .70 .68 .70


Proportion of scale score variance accounted for by the population-structure model, science PBA national assessment, by scale and grade: 2019
GradeNumber of initial conditioning contrastsNumber of principal componentsProportion of scale score variance
Univariate scalePhysical scienceEarth and space sciencesLife science
(Total Variance – Residual Variance) / Total Variance, where Total Variance includes variance accounted and unaccounted for by the variables in the population-structure model.
Excluding the constant term.
PBA = Paper-based assessment.
U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2019 Science Assessment.
41986600.64.65.69.61
82215639.67.69.68.68
122097610.73.76.73.73


Last updated 05 October 2023 (SK)