Table of Contents  |  Search Technical Documentation  |  References

NAEP Analysis and Scaling → Estimation of Population and Student Group Distributions → Examining the Population-Structure Models Used in NAEP → Proportion of Variance Accounted for By Principal Components Used in NAEP Population-Structure Models → Proportion of Variance of the Group-Defining Contrasts Accounted for by the Principal Components Used in the Population-Structure Model, Grade 8 Reading Combined National and State Main Assessment: 2007

NAEP Technical DocumentationProportion of variance of the group-defining contrasts accounted for by the principal components used in the population-structure model, grade 8 reading combined national and state main assessment: 2007

Type of contrast	Number of contrasts	Mean	Minimum	Maximum	Number of contrasts by proportion1 of variance explained
					0.00 - 0.70	0.70 - 0.80	0.80 - 0.90	0.90 - 0.95	0.95 - 1.00
1 (Total Variance – Residual Variance)/Total Variance, where Total Variance consists of both sampling and measurement error variance. NOTE: NIES = National Indian Education Study; SD/ELL = Students with disabilities/English language learners. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2007 Reading Assessment.
All contrasts	1710	0.90	0.55	1.00	23	116	584	527	460
Student questionnaire	215	0.90	0.55	0.99	2	14	72	78	49
Major reporting variables	113	0.93	0.68	1.00	1	4	18	40	50
Interactions between reporting variables	555	0.91	0.61	0.99	12	23	138	183	199
Teacher questionnaire	255	0.90	0.67	0.99	1	13	108	57	76
School questionnaire	270	0.89	0.73	0.98	0	22	114	106	28
NIES questionnaire	262	0.87	0.67	0.99	7	37	126	54	38
SD/ELL questionnaire	40	0.93	0.75	0.99	0	3	8	9	20

Printer-friendly Version