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 Mathematics Combined National and State Assessment, by Type of Contrast: 2017

Proportion of variance of the group-defining contrasts accounted for by the principal components used in the population-structure model, grade 8 mathematics combined national and state assessment, by type of contrast: 2017

Type of contrast	Number of contrasts	Mean	Minimum	Maximum	Number of contrasts by proportion of variance explained 1
					.00 - .70	.70 - .80	.80 - .90	.90 - .95	.95 - 1.00
All contrasts	1600	.90	.59	1.00	10	96	583	567	344
Student questionnaire	328	.92	.71	.99	0	16	68	140	104
Major reporting variables	160	.91	.74	1.00	0	4	61	48	47
Interactions between reporting variables	268	.89	.59	.98	10	15	94	110	39
Teacher questionnaire	417	.91	.73	.99	0	17	158	135	107
School questionnaire	396	.88	.73	.98	0	37	195	127	37
SD/EL questionnaire	31	.89	.71	.99	0	7	7	7	10
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), 2017 Mathematics Assessment.

Printer-friendly Version