NAEP Technical DocumentationMarket-Basket/Short-Form Mathematics Reporting Weights

The market-basket/short-form mathematics assessment, administered only at grade 4, was a compilation of five distinct subsamples of various market-basket/short-form mathematics assessments. Students selected for this assessment were randomly given a booklet corresponding to one of the five subgroups—designated as MB1, MB2, hybrid MB1, hybrid MB2, or linking forms. To facilitate the analyses of these subsamples, against one another and against the national main mathematics assessment, reporting weights were created for each subsample and reporting population. Each set of reporting weights was calculated so that the weights represented the same target population as the overall market-basket/short-form mathematics assessment—the grade 4 student population.

Reporting weights for the overall market-basket/short-form mathematics assessment used the same weighting procedures as the reporting weights for the mathematics and science main national assessments, up through the reporting factor. A separate subsampling factor (denoted SF_SUBWT) was applied to each reporting weight to account for the market-basket/short-form subsampling procedure. The table below shows the target sample size and subsampling factor for each market-basket/short-form mathematics subsample. Poststratification was then done separately on each set of reporting weights by subsample and reporting population.

Sample size and subsampling weighting factors for the market-basket/short-form mathematics subsamples: 2000
Market-basket/short-form mathematics subsamples	Sample size	Subsampling weighting factor
Total	8,000	†
MB1	2,000	4.0
MB2	2,000	4.0
Hybrid MB1	1,000	8.0
Hybrid MB2	1,000	8.0
Linking forms	2,000	4.0
† Not applicable. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2000.

Last updated 25 August 2008 (FW)

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