Preparing For the 2000 Census Interim Report II (1997) / Chapter Skim
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Sampling for Nonresponse Follow-up: Achieving Adequate Precision at Acceptable Cost
Sampling for Nonresponse Follow-up: Achieving Adequate Precision at Acceptable Cost
Pages 30-45
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From page 30... ...
We defer discussion of integrated coverage measurement to Chapter 6, except to the extent that details of that process are needed here. ALTERNATIVE DESIGNS FOR NONRESPONSE FOLLOW-UP The Census Bureau will provide more ways to be counted in the 2000 census than ever before.
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From page 31... ...
That plan calls for a two-stage design. During stage I, the Census Bureau would conduct follow-up by enumerators in the field to raise the response rate to at least 90 percent of housing units on the MAF in each census tract.6 Once the 90 percent mark has been reached, stage 2 follow-up would be conducted on a I-in-10 random sample of the remaining housing units.
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From page 32... ...
Nonresponse follow-up sampling rates would be set to achieve a final response rate of 90 percent in each census tract. For example, a I-in-2 sampling rate for nonespondents would be used in tracts with initial response rates of 80 percent, while a 5in-6 sampling rate would be used in tracts with a 40 percent response rate.
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From page 33... ...
Under each of the design alternatives, the current assumption is that the Census Bureau will use characteristics and counts from the sampled housing units to estimate corresponding characteristics and counts for the nonsampled units. For example, under 90 percent truncation design, with a I-in-10 sampling rate, data from each sampled household will be imputed to nine non sampled housing units.
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From page 34... ...
because there is little time to catch up. In initial discussions of the truncation designs, Census Bureau field managers anticipated that the transition from stage ~ to stage 2 of nonresponse follow-up would lead to a 1-week hiatus in enumeration operations, resulting in substantial staff loss, more than occurs during operations.
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From page 35... ...
. The final section of Table ~ presents a direct sampling design with sampling rates set to equalize the coefficient of variation among tracts of the same size, but with different initial response rates.
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From page 36... ...
Reached (in %) 40 91 1.64 90 .60 85.1 50 91 1.64 90 .61 85.8 60 91 1.64 90 .63 86.7 70 91 1.64 90 .67 88.1 75 91 1.64 90 .71 88.9 80 91 1.64 90 .77 90.0 85 91 1.64 90 .95 91.5 90 91 1.64 91 1.64 93.4 77 77 77 77 77 77 77 .77 NOTES: The table assumes: a constant tract size of n = 1,500 housing units; a constant ratio of 0.67 for the standard deviation of household size divided by the mean household size; and sample data that are weighted by the inverse of the sampling rate.
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From page 37... ...
~ percent or less under direct sampling. At this level of geography, variability due to nonresponse followup would be negligible compared with sampling variability due to integrated coverage measurement -- about 0.5 percent for most congressional districts (Killion, 1996b)
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From page 38... ...
If the response rate in a tract is still only 60 or 70 percent, the Census Bureau will need to choose among arbitrarily closing out a large number of units, delaying the beginning of stage 2, or modifying the sampling plan design. Direct sampling also offers the advantage of improved control over where data are collected relative to that for truncation designs.
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From page 39... ...
In focus groups conducted prior to the 1995 census test, residents of the test sites expressed particular concern about the use of sampling that begins before an effort to reach everyone but seemed more willing to accept sampling after response had already reached 90 percent (Research/Strategy/Management and Beldon & Russonello, 1995~. The Census Bureau also anticipates opposition to any plan that fails to reach at least 90 percent of households in every tract (such as the third design in Table I)
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From page 40... ...
We recognize that a variety of concerns may mitigate against our recommended nonresponse follow-up design. For example, should negative public reaction to final response levels below 90 percent necessitate setting a floor such as 90 percent for all census tracts, modifying the direct sampling design by setting a minimum sampling rate of at least ~ in 4 or ~ in 3 would avoid the worst inefficiency and ensure roughly equal accuracy across the range of initial response rates.
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From page 41... ...
that Is executed as planned Is far superior to a more ambitious design that runs short of time or resources. Unit of Sampling In the 1995 census test the Census Bureau evaluated two distinct methods for selection of the samples immediately after completion of the initial response period: a housing-unit sample, in which nonresponding units were sampled randomly from each block (possibly none in some blocks)
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From page 42... ...
Based on that evidence, the Census Bureau has decided to use a housing-unit sample in blocks without integrated coverage measurement. There was no evidence of a cost difference under 90 percent truncation and very little difference under direct sampling (Treat, 1996a)
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From page 43... ...
Under 90 percent truncation, just ~ percent of housing units in blocks without integrated coverage measurement would be visited during the stage 2 nonresponse follow-up, so that a block where an enumerator visits several units may stand out as unusual. One step to reduce identification of integrated coverage measurement blocks (Census Bureau field personnel may have better suggestions)
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From page 44... ...
Role of Administrative Records Prior to December 1996, Census Bureau plans called for administrative records (or combinations of records) to substitute for field enumeration for selected housing units.
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From page 45... ...
from administrative records and the census (see Chapter 7) make it unlikely that such art approach can be used effectively in 2000.
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