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NAEP Sample Design → NAEP 2005 Sample Design → National Assessment Sample Design → Private School National Assessment

NAEP Technical DocumentationPrivate School National Assessment

			Target Population Sampling Frame Stratification of Schools School Sample Selection Substitute Schools Ineligible Schools Student Sample Selection Participation

The private school sample (the "delta sample") was designed to produce a nationally representative school and student sample for all of the studies (operational, bridge, and pilot) among the students in private schools in the United States.

For each grade, private schools were divided into four strata based on school affiliation, and implicitly stratified within the four explicit strata. The table below shows target sample sizes for the student assessments for each assessment type (operational, science bridge, pilot), by private school stratum (Catholic, Lutheran, Conservative Christian, and other private), and overall, for fourth, eighth, and twelfth grades, respectively.

The design called for oversampling of specific private school groups for those assessments where state participation is required - namely grade 4 and grade 8 reading and mathematics. Consequently the private school samples for those assessments are much larger than for science and for grade 12.

Target sample sizes were adjusted for expected school and student response and eligibility.

 

Target student sample for private schools, by stratum, grade, and assessment: 2005

Sample	Total	Catholic	Lutheran	Conservative Christian	Other Private
Total fourth grade	16,040	8,025	1,693	2,107	4,215
Mathematics	6,000	3,000	750	750	1,500
Reading	6,000	3,000	750	750	1,500
Science	2,400	1,200	120	360	720
Science bridge	1,200	600	60	180	360
Pilot	440	225	13	67	135
Total eighth grade	16,090	8,050	1,696	2,114	4,230
Mathematics	6,000	3,000	750	750	1,500
Reading	6,000	3,000	750	750	1,500
Science	2,400	1,200	120	360	720
Science bridge	1,200	600	60	180	360
Pilot	490	250	16	74	150
Total twelfth grade	9,550	4,775	477	1,433	2,865
Mathematics	2,000	1,000	100	300	600
Reading	2,600	1,300	130	390	780
Science	2,900	1,450	145	435	870
Science bridge	1,200	600	60	180	360
Pilot	850	425	42	128	255
SOURCE: U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics, National Assessment of Educational Progress (NAEP), 2005.

Samples were based on a two-stage design that involved selection of schools within strata and selection of students within schools. The first-stage samples of schools were selected with probability proportional to a measure of size based on the estimated grade-specific enrollment in the schools.

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