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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 1999 Scores and 1999 Transformed Provisional Scores, Age 17 Reading Long-Term Trend Assessment: 2004

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 1999 scores and 1999 transformed provisional scores, age 17 reading long-term trend assessment: 2004
Statistic Original 1999 score 1999 transformed provisional score Difference between the provisional score and the original score
Mean 287.76 287.76 #
10th percentile 233.11 232.67 -0.44
25th percentile 260.68 260.66 -0.02
50th percentile 289.19 289.46 0.27
75th percentile 316.40 316.53 0.13
90th percentile 340.58 340.02 -0.56
# Rounds to zero.
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2004 Reading Long-Term Trend Assessment.

Last updated 27 April 2009 (JL)

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