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NAEP Sample Design → NAEP 2002 Sample Design → 2002 State Assessment Sample Design → School Sample Selection for the 2002 State Assessment → Sample Selection

NAEP Technical DocumentationSample Selection

			CCD Frame and New- School Sample Sizes Comparison of State NAEP School Samples Against the Public School Sampling Frame

The measure of size assigned to each school s in jurisdiction j is

The quantity b_j is the sampling parameter for the jurisdiction (the marginal increase in the measure of size for a school from adding one further student), MOS_js is the measure of size for each school (based on its enrollment), and u_j is an upper bound for the number of hits for any given school in the jurisdiction (see Computation of Measures of Size for details). The schools were ordered within each jurisdiction using a serpentine sort (by district status, urbanicity status, minority status, and achievement score or ZIP code area median income). A systematic sample was then drawn using this serpentine sort and the measures of size.

In addition, new and newly eligible schools from the new-school sampling frame selected for the sample were assigned measures of size.

using the b_j and u_j values from the main school sample for the jurisdiction (i.e., the same sampling rates were used for new schools as for Common Core of Data (CCD) schools within each jurisdiction, computed as described in Computation of Measures of Size). The new schools were ordered by district (i.e., the serpentine sort was not used for the small numbers of these schools), and a systematic sample drawn.

The objective in deeply stratifying the school sample in each jurisdiction is to reflect the population distribution as closely as possible, with as little sampling error as possible. One can judge the success of this method by checking percentages of minorities (CCD values for each school), median income, and type of location (viewed as an interval variable) for the original frame as against the school sample. In addition, one can check achievement levels for the original frame as against the school sample for those jurisdictions in which achievement levels were obtained.

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