NAEP Technical Documentation Proportion of Variance of the Group-Defining Contrasts Accounted for by the Principal Components Used in the Population-Structure Model, Grade 8 Science Combined National and State Assessment, by Type of Contrast: 2015

Proportion of variance of the group-defining contrasts accounted for by the principal components used in the population-structure model, grade 8 science combined national and state assessment, by type of contrast: 2015

Type of contrast	Number of contrasts	Mean	Minimum	Maximum	Number of contrasts by proportion of variance explained1
					.00 - .70	.70 - .80	.80 - .90	.90 - .95	.95 - 1.00
All contrasts	2054	.90	.64	1.00	8	69	946	648	383
Student questionnaire	257	.90	.64	.99	4	18	81	111	43
Major reporting variables	125	.92	.78	1.00	0	3	39	36	47
Interactions between reporting variables	384	.90	.66	.98	4	22	110	195	53
Teacher questionnaire	485	.91	.75	.99	0	15	215	144	111
School questionnaire	767	.89	.78	.99	0	8	488	155	116
SD/EL questionnaire	36	.90	.79	.99	0	3	13	7	13
1 (Total Variance – Residual Variance) / Total Variance, where Total Variance consists of sampling, measurement, and other sources of error. NOTE: SD/EL = Students with disabilities/English learners. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2015 Science Assessment.

Printer-friendly Version