NAEP Technical DocumentationComparisons of Means and Percentiles of Scores and Transformed Provisional Scores, Grade 4 Reading Combined National and State Assessment, by Scale: 2017

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.

In 2017, both a paper-based assessment (PBA) and a digitally based assessment (DBA) were administered. The provisional PBA estimates were transformed based on the procedures described above. Then a common population linking was used to align the 2017 paper-based assessment results with the 2017 digitally based assessment results.

Comparison of means and percentiles of 2015 PBA scores and 2015-transformed provisional PBA scores, grade 4 reading combined national and state assessment, by scale: 2015 and 2017

Scale	Statistic	Original 2015 PBA estimate	2015-transformed provisional PBA estimate	Difference between the provisional estimate and the original estimate
Composite	Mean	222.52	222.52	#
	10th percentile	173.92	172.38	-1.54
	25th percentile	200.74	199.65	-1.09
	50th percentile	226.14	226.09	-0.05
	75th percentile	247.99	248.56	0.56
	90th percentile	266.02	267.20	1.18
Reading for literary experience	Mean	224.35	224.35	#
	10th percentile	174.53	173.63	-0.90
	25th percentile	201.68	200.97	-0.71
	50th percentile	227.86	227.78	-0.08
	75th percentile	250.50	250.84	0.34
	90th percentile	269.39	269.91	0.53
Reading for information	Mean	220.69	220.69	#
	10th percentile	170.77	169.90	-0.86
	25th percentile	198.29	197.45	-0.84
	50th percentile	224.34	224.16	-0.18
	75th percentile	246.82	247.06	0.24
	90th percentile	265.49	266.23	0.74
# Rounds to zero. NOTE: The differences are based on the unrounded estimates. PBA = Paper-based assessment. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2015 and 2017 Reading Assessments.

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