NAEP Assessment Sample Design → NAEP 2011 Sample Design → Sample Design for the 2011 National Assessment → 2011 Writing Computer-Based Assessment (WCBA) → Selection of Primary Sampling Units for the 2011 WCBA and MCBS Assessments → Primary Sampling Unit Frame: Stratification for the 2011 Assessments → Final Primary Sampling Unit Strata for the 2011 Assessments

NAEP Technical DocumentationFinal Primary Sampling Unit (PSU) Strata for the 2011 Assessments

The strata were defined using the selected stratifiers from the stepwise regression analysis (see Stepwise Regression Analysis Results for PSU Stratification). The cutoffs were selected so that roughly equal measures of size were represented by each stratum.

Stratification for Northeast metropolitan noncertainty primary sampling units (PSUs), national assessment, by stratum: 2011

Stratum	Primary stratifier	Secondary stratifier	PSUs	Measure of size
† Not applicable. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2011 National Assessment.
Total	†	†	46	4,531,012
1	Percent child poverty <=10.1%	Percent Black <=15.9%	8	572,628
2	Percent child poverty <=10.1%	15.9%< Percent Black <=27.7%	2	533,970
3	10.1%< Percent child poverty <=12.5%	Percent Black <=14.9%	7	578,198
4	10.1%< Percent child poverty <=12.5%	14.9%< Percent Black <=38.2%	4	624,044
5	12.5%< Percent child poverty <=13.4%	†	5	543,994
6	13.4%< Percent child poverty <=15.1%	†	7	574,735
7	15.1%< Percent child poverty <=17%	†	5	516,879
8	17%< Percent child poverty <=20.7%	†	8	586,564
Mean	†	†	†	566,377

Stratification for Northeast non-metropolitan noncertainty primary sampling units (PSUs), national assessment, by stratum: 2011

Stratum	Primary stratifier	PSUs	Measure of size
† Not applicable. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2011 National Assessment.
Total	†	50	1,098,293
1	Percent child poverty <=15.7%	22	544,762
2	15.7%< Percent child poverty <=22.8%	28	553,531
Mean	†	†	549,147

Stratification for Midwest metropolitan noncertainty primary sampling units (PSUs), national assessments, by stratum: 2011

Stratum	Primary stratifier	Secondary stratifier	Tertiary stratifier	PSUs	Measure of size
† Not applicable. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2011 National Assessment. Stratification for Midwest non-metropolitan noncertainty primary sampling units (PSUs), national assessment, by stratum: 2011 Stratum Primary stratifier Secondary stratifier Tertiary stratifier PSUs Measure of size † Not applicable. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2011 National Assessment. Total † † † 249 3,505,128 1 Percent child poverty <=15.7% Percent college grd <=12.5% † 41 577,244 2 Percent child poverty <=15.7% 12.5%< Percent college grd <=36.0% Pct BHI <=4.2% 42 577,144 3 Percent child poverty <=15.7% 12.5%< Percent college grd <=36.0% 4.2%< Pct BHI <=8.5% 42 582,552 4 Percent child poverty <=15.7% 12.5%< Percent college grd <=36.0% 8.5%< Pct BHI <=41.4% 38 591,909 5 15.7%< Percent child poverty <=45.5% Percent college grd <=13.2% † 41 584,830 6 15.7%< Percent child poverty <=45.5% 13.2%< Percent college grd <=23.0% † 45 591,449 Mean † † † † 584,188 Stratification for South metropolitan noncertainty primary sampling units (PSUs), national assessment, by stratum: 2011 Stratum Primary stratifier Secondary stratifier Tertiary stratifier PSUs Measure of size † Not applicable. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2011 National Assessment. Total † † † 153 13,269,054 1 Percent child poverty <=22.7% Percent Black <=39.7% Percent Hispanic <=1.7% 17 596,069 2 Percent child poverty <=22.7% Percent Black <=39.7% 1.7%< Percent Hispanic <=2.6% 11 630,434 3 Percent child poverty <=22.7% Percent Black <=39.7% 2.6%< Percent Hispanic <=2.7% 3 578,311 4 Percent child poverty <=22.7% Percent Black <=39.7% 2.7%< Percent Hispanic <=3.0% 8 571,617 5 Percent child poverty <=22.7% Percent Black <=39.7% 3.0%< Percent Hispanic <=3.5% 8 663,600 6 Percent child poverty <=22.7% Percent Black <=39.7% 3.5%< Percent Hispanic <=4.2% 5 655,658 7 Percent child poverty <=22.7% Percent Black <=39.7% 4.2%< Percent Hispanic <=4.8% 4 626,966 8 Percent child poverty <=22.7% Percent Black <=39.7% 4.8%< Percent Hispanic <=5.5% 6 518,112 9 Percent child poverty <=22.7% Percent Black <=39.7% 5.5%< Percent Hispanic <=7.3% 8 589,272 10 Percent child poverty <=22.7% Percent Black <=39.7% 7.3%< Percent Hispanic <=8.5% 5 531,498 11 Percent child poverty <=22.7% Percent Black <=39.7% 8.5%< Percent Hispanic <=9.1% 3 701,272 12 Percent child poverty <=22.7% Percent Black <=39.7% 9.1%< Percent Hispanic <=11.2% 7 700,785 13 Percent child poverty <=22.7% Percent Black <=39.7% 11.2%< Percent Hispanic <=14.6% 8 571,531 14 Percent child poverty <=22.7% Percent Black <=39.7% 14.6%< Percent Hispanic <=21.1% 6 548,529 15 Percent child poverty <=22.7% Percent Black <=39.7% 21.1%< Percent Hispanic <=30.8% 5 691,494 16 Percent child poverty <=22.7% Percent Black <=39.7% 30.8%< Percent Hispanic <=51.2% 7 710,494 17 Percent child poverty <=22.7% 39.7%< Percent Black <=56.6% Percent Hispanic <=2.7% 6 547,257 18 Percent child poverty <=22.7% 39.7%< Percent Black <=56.6% 2.7%< Percent Hispanic <=7.8% 6 655,387 19 22.7%< Percent child poverty <=24.3% † † 11 498,732 20 24.3%< Percent child poverty <=45.7% Percent Black <=2.0% † 4 712,425 21 24.3%< Percent child poverty <=45.7% 2.0%< Percent Black <=60.8% Percent Hispanic <=3.8% 10 494,418 22 24.3%< Percent child poverty <=45.7% 2.0%< Percent Black <=60.8% 3.8%< Percent Hispanic <=64.1% 5 475,193 Mean † † † † 603,139 Stratification for South non-metropolitan noncertainty primary sampling units (PSUs), national assessment, by stratum: 2011 Stratum Primary stratifier Secondary stratifier Tertiary stratifier PSUs Measure of size † Not applicable. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2011 National Assessment. Total † † † 269 5,190,589 1 Percent Black <=31.2% Median HH income <=$36,049 Percent Asian <=0.2% 32 511,172 2 Percent Black <=31.2% Median HH income <=$36,049 0.2%< Percent Asian <0.3% 29 515,004 3 Percent Black <=31.2% Median HH income <=$36,049 Percent Asian =0.3% 32 520,184 4 Percent Black <=31.2% Median HH income <=$36,049 0.3%< Percent Asian <=0.4% 29 510,176 5 Percent Black <=31.2% Median HH income <=$36,049 0.4%< Percent Asian <=0.7% 26 538,940 6 Percent Black <=31.2% Median HH income <=$36,049 0.7%< Percent Asian <=3.0% 26 542,335 7 Percent Black <=31.2% $36,049< Median HH income <=$54,721 † 21 551,780 8 31.2%< Percent Black <=51.3% Median HH income <=$29,555 † 25 513,918 9 31.2%< Percent Black <=51.3% $29,555< Median HH income <=$44,421 † 22 499,209 10 51.3%< Percent Black <=79.4% † † 27 487,871 Mean † † † † 519,059 Stratification for West metropolitan noncertainty primary sampling units (PSUs), national assessment, by stratum: 2011 Stratum Primary stratifier Secondary stratifier PSUs Measure of size † Not applicable. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2011 National Assessment. Total † † 71 6,803,588 1 Percent high school graduates <=70% Percent college graduates <=13.5% 7 635,482 2 Percent high school graduates <=70% 13.5%< Percent college graduates <=22.5% 4 508,977 3 70%< Percent high school graduates <=78.9% † 6 513,746 4 78.9%< Percent high school graduates <=79.6% † 3 656,056 5 79.6%< Percent high school graduates <=88.3% Percent college graduates <=21.8% 14 559,117 6 79.6%< Percent high school graduates <=88.3% 21.8%< Percent college graduates <=25.5% 8 587,808 7 79.6%< Percent high school graduates <=88.3% 25.5%< Percent college graduates <=26.9% 4 525,628 8 79.6%< Percent high school graduates <=88.3% 26.9%< Percent college graduates <=27.8% 3 583,877 9 79.6%< Percent high school graduates <=88.3% 27.8%< Percent college graduates <=30.3% 3 557,408 10 79.6%< Percent high school graduates <=88.3% 30.3%< Percent college graduates <=39.5% 3 527,923 11 88.3%< Percent high school graduates <=90.1% † 8 556,141 12 90.1%< Percent high school graduates <=93.1% † 8 591,425 Mean † † † 555,966
Total	†	†	†	100	7,458,159
1	Percent child poverty <=12.5%	†	Pct Asian <=1.1%	17	623,684
2	Percent child poverty <=12.5%	†	1.1%< Pct Asian <=1.4%	4	668,332
3	Percent child poverty <=12.5%	†	1.4%< Pct Asian <=2.4%	8	598,589
4	Percent child poverty <=12.5%	†	2.4%< Pct Asian <=2.6%	3	706,518
5	Percent child poverty <=12.5%	†	2.6%< Pct Asian <=3.4%	7	602,499
6	Percent child poverty <=12.5%	†	3.4%< Pct Asian <=10.3%	13	618,908
7	12.5%< Percent child poverty <=12.9%	†	†	6	619,810
8	12.9%< Percent child poverty <=14.5%	†	Pct Asian <=1.3%	7	623,599
9	12.9%< Percent child poverty <=14.5%	†	1.3%< Pct Asian <=2.7%	7	602,409
10	14.5%< Percent child poverty <=27.6%	Med HH Income <=$38,291	†	17	603,071
11	14.5%< Percent child poverty <=27.6%	$38,291< Med HH Income <=$46,460	Pct Asian <=0.9%	7	569,605
12	14.5%< Percent child poverty <=27.6%	$38,291< Med HH Income <=$46,460	0.9%< Pct Asian <=3.1%	4	621,135
Mean	†	†	†	†	621,513

Stratification for West non-metropolitan noncertainty primary sampling units (PSUs), national assessment, by stratum: 2011

Stratum	Primary stratifier	Secondary stratifier	Tertiary stratifier	PSUs	Measure of Size
† Not applicable. SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2011 National Assessment.
Total	†	†	†	102	1,678,098
1	Percent college graduates <=21%	Percent child poverty <=17.3%	†	26	425,522
2	Percent college graduates <=21%	17.3%<Percent child poverty <=43%	Percent HS graduates <=77.3%	23	409,676
3	Percent college graduates <=21%	17.3%<Percent child poverty <=43%	77.3%< Percent HS graduates <=86.4%	28	409,881
4	21%< Percent college graduates <=42.6%	†	†	25	433,019
Mean	†	†	†	†	419,525

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