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School-Level Replicate Weights

Each replicate sample had to be reweighted to compensate for the dropped unit(s) defining the replicate. This reweighting was done in two stages. At the first-stage, the ith school included in a particular replicate r was assigned a replicate-specific school base weight defined as:

W superscript t s c h sub r i equals K sub r multiplied by W superscript t s c h sub i,

where W superscript t s c h sub i is the full-sample base weight for school i, and where

K sub r = 1.5 if school i was contained in a quote pair unquote consisting of 3 units from which the complimentary member was dropped to form replicate r, K sub r = 2 if school i was contained in a pair consisting of 2 units from which the compliment ary member was dropped to form replicate r, K sub r = 0 if school i was dropped to form replicate r, and K sub r = 1 if school i was not assigned to replicate r, or if school i was a certainty.

For students with a disability and limited-English-proficient students in American Samoa, Guam, Virgin Islands, and the Department of Domestic Dependent Elementary and Secondary Schools grade 8:

K sub r = n divided by the quantity n - 1 if school i was not dropped in forming replicate r, and K sub r = 0 if school i was dropped to form replicate r.

Using the replicate-specific school base weights, W superscript t s c h sub rithe school-level nonresponse weighting adjustments were recalculated for each replicate r. That is, the school-level nonresponse adjustment factor for schools in replicate r and adjustment class k was computed as:

F sub r k = open bracket the summation over i an element of C sub k of open paren W superscript t s c h sub r k i multiplied by E sub k i closed paren closed bracket divided by open bracket the summation over i an element of C sub k of open paren W superscript t s c h sub r k i multiplied by E sub k i multiplied by delta sub r k i

where

Ck = the eligible sampled schools in adjustment class k,

W superscript t s c h sub r k i = the replicate-r base weight of the ith school in class k, and

Eki = the grade enrollment for the ith school in class k.

In the above formulation, the indicator variable delta sub r k i had a nonzero value only when the ith school in replicate r and adjustment class k participated in the assessment. The replicate-specific nonresponse-adjusted school weight for the ith school in replicate r in class k was then computed as:

W superscript s c h a d j sub r k i = F sub r k multiplied by W superscript t s c h sub r k i multiplied by delta sub r k i.

Last updated 26 August 2008 (FW)

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National Center for Education Statistics - http://nces.ed.gov
U.S. Department of Education