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NAEP Analysis and ScalingScale Linking and Transformation to the Reporting MetricComparisons of Distributions of Linking Samples for NAEP Assessments → Comparison of Means and Percentiles of Scores and Transformed Provisional Scores, Grade 12 Science National Assessment, by Scale: 2019

​​NAEP Technical DocumentationComparison of Means and Percentiles of Scores and Transformed Provisional Scores, Grade 12 Science National Assessment, by Scale: 2019

In 2019, both a paper-based assessment (PBA) and a digitally based assessment (DBA) were administered. PBA estimates are based on the PBA sample scale score results on the reporting metric. Provisional DBA estimates are based on DBA sample scaling results. These are on the theta metric specified by the scaling program. The PBA estimates and provisional DBA estimates are used to find the transformation constants necessary to place the DBA sample scale scores on the scale used to report previous assessment scale scores. The transformed DBA estimates are based on DBA sample scaling results, transformed to the reporting metric using the transformation constants calculated from the PBA estimates and provisional DBA estimates. If the transformation constants are correct, the PBA and transformed DBA means should be the same.

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 2019 PBA sample 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 2019 PBA sample scale scores on the scale used to report previous assessment scale scores. The transformed provisional estimates are based on previous assessment data and 2019 PBA sample 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 2019 PBA scores and 2019-transformed provisional scores, grade 12 science DBA national assessment, by scale: 2019
Statistic Original 2019 PBA estimate 2019 DBA-transformed provisional estimate Difference between the provisional estimate and the original estimate
Rounds to zero.
PBA = Paper-based assessment. DBA = Digitally based assessment. The differences are based on the unrounded estimates.
U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2019 Science Assessment.
Univariate scale
Mean 149.57 149.57
10th percentile 100.74 100.18 -0.57
25th percentile 124.80 124.55 -0.26
50th percentile 150.88 151.03 0.15
75th percentile 175.49 175.93 0.45
90th percentile 196.90 196.85 -0.05
Physical science
Mean 148.59 148.59
10th percentile 100.98 100.61 -0.36
25th percentile 124.08 123.33 -0.75
50th percentile 148.98 148.81 -0.17
75th percentile 173.39 174.16 0.77
90th percentile 195.95 196.20 0.25
Earth and space sciences
Mean 150.33 150.33
10th percentile 104.60 103.67 -0.94
25th percentile 127.13 126.82 -0.31
50th percentile 151.58 151.75 0.16
75th percentile 174.78 175.23 0.45
90th percentile 194.94 194.90 -0.04
Life science
Mean 150.16 150.16
10th percentile 99.89 99.44 -0.45
25th percentile 124.71 124.76 0.05
50th percentile 151.72 151.96 0.25
75th percentile 176.98 177.16 0.18
90th percentile 198.55 198.22 -0.33


Comparison of means and percentiles of 2015 scores and 2015-transformed provisional scores, grade 12 science PBA national assessment, by scale: 2015 and 2019
StatisticOriginal 2015 PBA estimate2015 PBA-transformed provisional estimateDifference between the provisional estimate and the original estimate
Rounds to zero.
PBA = Paper-based assessment. The differences are based on the unrounded estimates.
U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2015 and 2019 Science Assessments.
Univariate scale
Mean150.23150.23
10th percentile102.84102.79-0.04
25th percentile126.09126.240.15
50th percentile151.43151.470.04
75th percentile175.50175.510.01
90th percentile196.01195.92-0.10
Physical science
Mean150.00150.00
10th percentile103.67102.57-1.10
25th percentile125.55125.44-0.11
50th percentile149.93150.540.61
75th percentile174.35174.780.43
90th percentile196.74196.68-0.05
Earth and space sciences
Mean150.68150.68
10th percentile107.17106.40-0.77
25th percentile128.40128.460.06
50th percentile151.36151.970.60
75th percentile173.87174.450.58
90th percentile193.59193.12-0.48
Life science
Mean150.57150.57
10th percentile103.20102.64-0.57
25th percentile125.97126.360.39
50th percentile151.41152.120.71
75th percentile176.21176.220.01
90th percentile197.39196.93-0.46


Last updated 05 October 2023 (SK)