NAEP Technical DocumentationComparison of Means and Percentiles of 2009 Scores and 2009-Transformed Provisional Scores, Grade 4 Science Combined National and State Assessment, by Scale: 2015

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. Prior to transformation, provisional estimates 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.

Comparison of means and percentiles of 2009 scores and 2009-transformed provisional scores, grade 4 science combined national and state assessment, by scale: 2015

Scale	Statistic	Original 2009 estimate	2009-transformed provisional estimate	Difference between the provisional estimate and the original estimate
Composite	Mean	150.00	150.00	#
	10th percentile	103.53	103.24	-0.29
	25th percentile	127.87	127.41	-0.46
	50th percentile	152.87	152.60	-0.27
	75th percentile	175.06	175.07	0.01
	90th percentile	192.47	193.06	0.59
Physical science	Mean	150.00	150.00	#
	10th percentile	103.83	103.98	0.15
	25th percentile	128.17	127.38	-0.79
	50th percentile	152.72	151.96	-0.76
	75th percentile	174.65	174.63	-0.02
	90th percentile	192.43	193.47	1.04
Earth and space sciences	Mean	150.00	150.00	#
	10th percentile	103.59	103.54	-0.05
	25th percentile	127.27	126.54	-0.73
	50th percentile	152.13	151.66	-0.47
	75th percentile	174.87	174.89	0.02
	90th percentile	193.20	193.91	0.71
Life science	Mean	150.00	150.00	#
	10th percentile	104.29	104.12	-0.17
	25th percentile	127.66	127.19	-0.47
	50th percentile	151.93	151.63	-0.30
	75th percentile	174.39	174.51	0.12
	90th percentile	193.26	193.67	0.41
# Rounds to zero. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2015 Science Assessment.

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