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 of the Group-Defining Contrasts Accounted for by the Principal Components Used in NAEP Student Group Distribution Models → Proportion of Variance of the Group-Defining Contrasts Accounted for by the Principal Components Used in the Population-Structure Model, Age 17 Reading Long-Term Trend Assessment: 2004

NAEP Technical DocumentationProportion of variance of the group-defining contrasts accounted for by the principal components used in the population-structure model, age 17 reading long-term trend assessment: 2004

Type of contrast	Number of contrasts	Mean	Minimum	Maximum	Number of contrasts by proportion1 of variance explained
					0.00 - 0.70	0.71 - 0.80	0.81 - 0.90	0.91 - 0.95	0.96 - 1.00
1(Total Variance – Residual Variance)/Total Variance, where Total Variance consists of both sampling and measurement error variance. NOTE: Teacher and school questionnaires were not included in the long-term trend assessments in 2004. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2004 Reading Long-Term Trend Assessment.
All contrasts	791	0.90	0.59	0.98	10	47	253	341	140
Student questionnaire	55	0.88	0.64	0.97	2	10	13	21	9
Major reporting variables	37	0.91	0.66	0.97	1	1	9	12	14
Interactions between reporting variables	699	0.90	0.59	0.98	7	36	231	308	117

Printer-friendly Version