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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 Original 2000 Scores and 2000 Transformed Provisional Scores, Grade 4 Science Combined National and State Main Assessment, by Scale: 2005

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 original 2000 scores and 2000 transformed provisional scores, grade 4 science combined national and state main assessment, by scale: 2005

Scale	Statistic	Original 2000 score	2000 transformed provisional score	Difference between the provisional score and the original score
Composite scale	Mean	146.79	146.79	#
	10th Percentile	98.96	99.37	-0.41
	25th Percentile	124.50	124.44	0.06
	50th Percentile	149.80	149.55	0.25
	75th Percentile	172.30	172.01	0.29
	90th Percentile	189.71	189.73	-0.02
Physical science	Mean	146.28	146.28	#
	10th Percentile	96.97	97.37	-0.40
	25th Percentile	123.27	122.70	0.57
	50th Percentile	149.43	148.83	0.60
	75th Percentile	172.57	172.45	0.12
	90th Percentile	191.17	191.70	-0.53
Earth science	Mean	148.43	148.43	#
	10th Percentile	99.20	99.54	-0.34
	25th Percentile	124.93	125.20	-0.27
	50th Percentile	151.32	151.07	0.25
	75th Percentile	174.78	174.66	0.12
	90th Percentile	193.73	193.70	0.03
Life science	Mean	145.67	145.67	#
	10th Percentile	97.17	97.20	-0.03
	25th Percentile	122.94	123.22	-0.28
	50th Percentile	148.85	148.68	0.17
	75th Percentile	171.38	171.37	0.01
	90th Percentile	189.71	189.82	-0.11
# Rounds to zero. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2005 Science Assessment.

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