Adult Literacy in America - National Center for Education Statistics ...

The sample designs for all 12 household samples involved four stages of
selection, each at a successively finer level of geographic detail. The first stage of
sampling involved the selection of PSUs, which consist of counties or groups of
counties. The PSUs were stratified on the basis of region, metropolitan status,
percent Black, percent Hispanic, and, whenever possible, per capita income. The
national component used the WESTAT 100 PSU master sample with the
Honolulu, Hawaii PSU added to the sample with certainty, to make 101 PSUs in
total. The national frame of PSUs was used to construct individual state frames
for the state component and a sample of eight to 12 PSUs was selected within
each of the given states. All PSUs were selected with probability proportional to
the PSU’s 1990 population.
The second stage of sampling involved the selection of segments (within the
selected PSUs) which consist of census blocks or groups of census blocks. The
segments were selected with probability proportional to size where the measure
of size for a segment was a function of the number of year-round housing units
within the segment. The oversampling of Black and Hispanic respondents for the
national component was carried out at the segment level, where segments were
classified as high minority (segments with more than 25 percent Black or
Hispanic population) or not high minority. The measure of size for high minority
segments was defined as the number of White non-Hispanic households plus
three times the number of Black or Hispanic households. High minority segments
were therefore oversampled at up to three times the rate of comparable, nonhighminority
segments. The measure of size for nonminority segments was
simply the number of year-round housing units within the segment, as was the
measure of size for all segments in the state components. One in 7 of the national
component segments was selected at random to be included in a “ no incentive”
sample. Respondents from the remaining segments in the national component
received a monetary incentive for participation, as did respondents in the state
component. (Respondents from the “ no incentive” segments are not included in
the household sample of this report.)
The third stage of sampling involved the selection of households within the
selected segments. Westat field staff visited all selected segments and prepared
lists of all housing units within the boundaries of each segment as determined by
the 1990 census block maps. The lists were used to construct the sampling frame
for households. Households were selected with equal probability within each
segment, except for White non-Hispanic households in high minority segments in
the national component, which were subsampled so that the sampling rates for
White non-Hispanic respondents would be about the same overall.
The fourth stage of sampling involved the selection of one or two adults
within each selected household. A list of age-eligible household members (16 and
114 ......Appendix A