NAEP Assessment Sample Design → NAEP 2012 Sample Design → Selection of Primary Sampling Units (PSU's) for the 2012 Assessment → Final Primary Sampling Unit Sample for the 2012 Assessment

NAEP Technical DocumentationFinal Primary Sampling Unit Sample for the 2012 Assessment

For the Long-Term Trend (LTT) assessment, a sample of 67 primary sampling units (PSUs) was selected (29 certainties and 38 noncertainties). To accomplish this, the 76 noncertainty strata (defined in Final Primary Sampling Unit Strata) were paired and one noncertainty stratum was randomly selected from each of the 38 pairs.  Then one PSU was selected from each of the 38 selected strata with probability proportionate to size (with size equal to the estimated number of youths).

For the Economics assessment, a sample of 67 PSUs was also drawn. The same certainty PSUs were included in the non-LTT sample, but the noncertainty PSUs were drawn from the 38 noncertainty strata that were not used for the LTT assessment. Thus the two sets of sampled noncertainty PSUs were distinct from each other and did not overlap. In addition, the noncertainty PSUs were selected in such a way as to minimize overlap with PSU samples from prior NAEP assessments. 

Distribution of sampled primary sampling units (PSU) for long-term trend (LTT) and economics assessments by PSU type: 2012

PSU type	Number of sampled PSUs
	LTT	Economics
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2012.
Total	67	67
Metropolitan status
Metropolitan	56	56
Non-metropolitan	11	11
Census Region
Northeast	10	10
Midwest	14	14
South	26	26
West	17	17
Certainty/metropolitan status
Certainty	29	29
Non-certainty metropolitan	27	27
Non-certainty non-metropolitan	11	11

Printer-friendly Version