NAEP Technical DocumentationStratification for Midwest Non-Metropolitan Noncertainty Primary Sampling Units

The following table provides the definition, number of PSUs, and size of each noncertainty PSU stratum in the Midwest non-metropolitan primary stratum. Columns 2 and 3 show the primary and secondary characteristics used to define the strata along with their respective cutoffs. The size of each stratum is given in the last column and is in terms of the number of youths (persons 17 years of age and younger).

Stratification for Midwest non-metropolitan noncertainty primary sampling units (PSUs), by stratum: 2018

Stratum	Primary stratifier	Secondary stratifier	PSUs	Measure of size
Total	†	†	228	3,423,867
1	Percentage of children below the poverty line <= 16.1	Percentage of children below the poverty line <= 13.7	41	578,068
2	Percentage of children below the poverty line <= 16.1	Percentage of children below the poverty line > 13.7	36	584,857
3	Percentage of children below the poverty line (16.1-20.7]	Percentage of Black, Hispanic, American Indian/Alaska Native, or Native Hawaiian/Other Pacific Islander youth <= 5.4	38	562,740
4	Percentage of children below the poverty line (16.1-20.7]	Percentage of Black, Hispanic, American Indian/Alaska Native, or Native Hawaiian/Other Pacific Islander youth > 5.4	37	566,454
5	Percentage of children below the poverty line > 20.7	Percentage of children below the poverty line <= 24	38	561,298
6	Percentage of children below the poverty line > 20.7	Percentage of children below the poverty line > 24	38	570,450
Mean	†	†	†	570,645
† Not applicable. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2018 Assessment.

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