A Census that Mirrors America Interim Report (1993) / Chapter Skim
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2 SAMPLING AND STATISTICAL EXTIMATION
2 SAMPLING AND STATISTICAL EXTIMATION
Pages 24-40
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From page 24... ...
(3) Sampling for content is also very likely in 2000 -- involving either a single long form assigned to a sample of households, as in 1990, or multiple sample forms (matrix sampling)
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From page 25... ...
Thus, methods that reduce the scope of nonresponse follow-up without undue sacrifices in the accuracy of the count or the content deserve serious consideration for the year 2000. Major Nonresponse FoBow-Up Innovations The Census Bureau is considering three main techniques that would greatly reduce the cost of nonresponse follow-up: truncation, shortening the time period for field operations; sampling, carrying out nonresponse follow-up operations for a sample of households or blocks; and use of administrative records to replace some of the field data collection.
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From page 26... ...
Third, coverage measurement methods that compare their own enumeration to the regular census enumeration in the same blocks would work much better in blocks, where all nonresponding households are followed up (see descriptions of CensusPlus and PES in He next section)
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In contrast to these cost and operational advantages, both truncation and sampling have negative implications for the precision of small-area enumeration. Truncation of nonresponse follow-up could be expected to increase both the undercount and differential coverage of regular census enumeration.
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We recommend that the Census Bureau include the testing of sampling in follow-up as part of the 1987 pretest program. We recommend that in its research the Census Bureau emphasize tests of sampling for the later stages of follow-up.
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From page 29... ...
COVERAGE MEASUREMENT METHODS Previous Coverage Measurement Programs The Census Bureau has attempted to systematically measure coverage of the census since 1950 (Coale, 1955; Himes and Clogg, 1992~. The 1980 PostEnumeration Program was designed as an evaluation program for the 1980 census.
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From page 30... ...
The Census Bureau's coverage evaluation efforts have demonstrated that certain groups are systematically undercounted relative to the rest of the population. Although response improvement programs -- such as questionnaire simplification and reminder postcards -- show promise for improving the Aback rate compared with 1990, early tests (see Chapter 3)
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From page 31... ...
Recommendation 2.3: We endorse the Census Bureau's stated goal of achieving a one-number census in 2000 that incorporates the results from coverage measurement programs, including programs involving sampling and statistical estimation, into the official census population totals. We recommend that research on alternative methodologies continue in pursuit of this goal.
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From page 32... ...
The key difference between CensusPlus and PES is that CensusPlus does not require independence between the basic enumeration and coverage measurement operations. This characteristic allows CensusPlus to use and build on the information collected during the regular census operations.
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33 Recommendation 2.4: Before final design of the 1995 census test, the Census Bureau should critically evaluate the SuperCensus method of coverage measurement by using 1990 data to team whether adequately precise coverage estimates are possible using ratios to the housing base. As noted in Chapter I, definitions of residency in a particular location are an issue for every coverage measurement method, complicated by people who move shortly after the census or whose residency is transient around census day.
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From page 34... ...
Because the PES is the method that is best supported by past experience, we believe it should be tested in combination with new features that will be tried in 1995, possibly including integrated coverage measurement, multiple response modes, and nonresponse follow-up truncation. In particular, the timeliness of the PES as pot of an integrated coverage measurement strategy can only be demonstrated in a census test environment.
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From page 35... ...
In addition to cost considerations, it would be important to demonstrate that field management and data processing operations for a larger coverage measurement program could be administered. Recommendation 2.6: Whatever coverage measurement method is used in 2000, the Census Bureau should ensure that a sufficiently large sample is taken so that the single set of counts provides the accuracy needed by data users at
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From page 36... ...
, and there is an opportunity to expand content by asking more questions without making any single form excessively long. Matrix sampling also has some liabilities that will have to be addressed in order to determine whether its use in the census win be beneficial: sample size for some cross-tabulations may be decreased; the best estimates for tabulations and cross-tabulations for some items will require use of statistical estimation methods; analysis of the resulting data products will be more complicated than with a single sample; and costs may increase due to increased content and operational complexity.
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From page 37... ...
The 1995 census test cannot provide decisive information on variances of interest because the correlation structure within and across pertinent geographic areas cannot be simulated from a test census conducted at only four sites. Research must also be carTied out to examine the operational feasibility, cost, and effects on bias and variance of the implementation of matrix sampling in combination with other basic census designs under consideration.
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From page 38... ...
While simulations with 1990 data may partly answer questions of this sort, testing in 199S will be necessary to fully explore these issues, especially those related to operations and costs. Recommendation 2.7: The Census Bureau should continue research on possible matrix sampling designs, using the 1990 census data to simulate tabulations and crosstabulations.
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From page 39... ...
As noted above, the use of matrix sampling implies the use of estimation to combine information from venous sample forms efficiently and to estimate cross-tabulations for which there is little or no information in the sample data. Necessary research on statistical estimation divides roughly into three phases.
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From page 40... ...
Similar models may be a useful tool for evaluating uncertainty in integrated estimates from a complex census in Me year 2000. Recommendation 2.9: The Census Bureau should develop methods for measuring and modeling all sources of error in the census and for showing uncertainty in published tabulations or otherwise enabling users to estimate uncertainty.
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