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NAEP Analysis and Scaling → Scale Linking and Transformation to the Reporting Metric → Comparisons of Distributions of Linking Samples for NAEP Assessments → Comparison Means and Percentiles of 1998 Scores and 2002 Transformed Provisional Scores in Writing at Grade 8, by Scale: 2002

Original estimates are based on previous assessment data and previous assessment scaling results, transformed to the reporting metric using the transformation identified during the analysis of the previous assessment data. Provisional estimates are based on previous assessment data and current assessment scaling results. These are on the theta metric specified by the scaling program. The original and provisional estimates for the linking sample are used to find the transformation constants necessary to place the current assessment scale scores on the scale used to report previous assessment scale scores. The transformed provisional estimates are based on previous assessment data and current assessment scaling results, transformed to the reporting metric using the transformation constants calculated from the original and provisional estimates for the linking sample. If the transformation constants are correct, the original and transformed provisional means should be the same.

NAEP Technical DocumentationComparison means and percentiles of 1998 scores and 2002 transformed provisional scores in writing at grade 8, by scale: 2002

Scale	Statistic	1998 scores	2002 transformed provisional scores	Difference between the 2002 provisional scores and the 1998 scores
Composite	Mean	150.00	150.00	#
	10th percentile	103.73	103.54	-0.19
	25th percentile	126.61	127.10	0.49
	50th percentile	151.27	151.80	0.53
	75th percentile	174.60	174.73	0.13
	90th percentile	194.07	193.67	-0.40
# Rounds to zero. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2002 Writing Assessment.

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