Reengineering the 2010 Census Risks and Challenges (2004) / Chapter Skim
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4 American Community Survey
4 American Community Survey
Pages 103-138
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From page 103... ...
The emergence of the statistical theory of survey sampling in the early 20th century brought with it the potential to collect detailed characteristics information without unduly burdening the entire American public. Asking detailed characteristics information from only a sample of the populace began in the 1940 census, when six questions on socioeconomic status were asked of only 5 percent of respondents.
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From page 104... ...
. A major household survey intended to include 250,000 housing units each month, the ACS would replace the decennial census longform sample and permit continuous measurement of the same data items currently collected only every 10 years on the census long form.
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From page 105... ...
. 4-A.1 Test Sites anal the Census 2000 Supplementary Survey Though the ACS was ruled out as a replacement for the long form in 2000, the mid-1990s burst of research and writing about the prospects of continuous measurement launched a wider research and evaluation effort.
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From page 106... ...
Data collection continued at these levels in 2001-2003. A report prepared as part of the 2000 census evaluation program concluded that operating a large continuous measurement survey in parallel with the decennial census was operationally feasible, based on the 2000 census and C2SS experience (Griffin and Obenski, 2001)
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From page 107... ...
This design choice is advantageous in that it simplifies data processing and production load there is no need to wait until month t+2 for final resolution of all the housing units chosen in month t before processing responses already submitted. But it does raise complex methodological challenges, including the choice of weighting methods to address unit nonresponse.
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From page 108... ...
· For all but the largest population or geographic groups, ACS estimates will be based on averages across multiple years of data. Is the ACS able to satisfy all of the needs currently addressed by long-form data, or are there applications based on the census long form for which substitution
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From page 109... ...
4-C ESTIMATION USING THE ACS 4-C.1 Adequacy of Moving Averages as Point Estimates A basic concern about the American Community Survey as a replacement for the census long form is whether ACS estimates which, particularly for small areas or groups, would be moving averages of multiple years' data points can effectively replace fixed-point-in-time estimates. Specifically, the concern is whether fund allocation formulas or other public and private planning needs for demographic data can be addressed using a combination of data from multiple years.
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From page 110... ...
Intuitively, it is sensible that, when examining data series in which change is substantial between decennial census years, moving average estimates would be preferable to seriously outdated estimates. When there is little change through the decade, there should be little difference between the two estimates.
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From page 111... ...
Along the same lines, moving averages present the same types of problems when they are used as dependent variables in various statistical models, in particular time-series models, and in some regression models. Therefore, the Census Bureau could bolster the case for the ACS and potentially help relieve users' concerns if it produced a user's guide that details the statistical uses for which moving averages are and are not ~ntended, the problems they pose to users, and the means to overcome them.
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From page 112... ...
4-D QUALITY OF ACS ESTIMATES The error associated with ACS data may be decomposed into sampling error (sample variance) and nonsampling error, the
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From page 113... ...
and CATI Nonresponse is widely variable and could be appreciable in some small areas.3 As a result, the Census Bureau is considering raising the sampling rate for CAPI follow-up for areas with high mad! and telephone nonresponse to make this source of sampling error more comparable across areas.
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From page 114... ...
(2003) use a measure of completeness similar to that used in census processing to determine if a household data record is complete enough to be considered "data-defined." To be complete under this metric, at least one member of the household had to have answered two of the basic completecount items asked on the census short form (e.g., age or sex)
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From page 115... ...
that it is reasonable to compare item imputation rates to measure the impact on data quality from item nonresponse. Item imputation rates for the C2SS were substantially lower than those for the 2000 census for the basic data items on both the short and long forms.
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From page 116... ...
In 2000, self responses included mail, telephone, Internet, and Be Counted returns; enumerator responses included forms obtained in nonresponse follow-up, list/enumerate, and other field operations. In the C2SS, self responses included mail; enumerator responses included forms obtained in telephone and in-person follow-up.
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From page 117... ...
This impact could be measured either through a reinterview survey or through matching to a more reliable source of data (possibly administrative records or highly reliable household surveys)
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From page 118... ...
More recently, the IRS has facilitated limited administrative records research by the Census Bureau using IRS data with appropriate safeguards.
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From page 119... ...
Currently, using census data to develop lower bounds on the amount of year-to-year change for various estimates for example, poverty rates involves examining census-to-census differences and dividing by ten whereas this annual change can be measured directly under the ACS. Operationally, relative to the decennial census, the prime advantage of a full-fledged ACS for the Census Bureau is the prospect of a short-form-only census.
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From page 120... ...
The ACS may eventually permit researchers to develop an integrated framework for more accurate small-area estimation, perhaps combining one or more waves of ACS data with results from administrative records, other household surveys, and the short-form decennial census. This broader framework would
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From page 121... ...
There are a variety of synergies that can be imagined between the ACS and household surveys such as the Current Population Survey, each drawing on the other to improve the information collected. As we commented in detail in Section 4-D, much work must be done to clarify the quality and accuracy of ACS estimates from a statistical standpoint.
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From page 122... ...
Although we believe that the proposed continuous measurement system deserves serious evaluation, we conclude that much work remains to develop credible estimates of its net costs and to answer many other fundamental questions about data quality, the use of small-area estimates based on cumulated data, how continuous measurement could be integrated with existing household surveys, and its advantages compared with other means of providing more Tithe remarks are quoted from the director's prepared testimony before the U.S. House Subcommittee on Technology, Information Policy, Intergovernmental Relations, and the Census at a hearing on the ACS' potential to replace the census long form in 2010.
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From page 123... ...
In summary, the pane! appreciates the enormous potential benefit of the ACS of having a program for continuous measurement of key social and demographic variables of national interest.
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From page 124... ...
Again, with appropriate safeguards, the Census Bureau should release ACS data to the broader research community for evaluation purposes. Recommendation 4.3: The Census Bureau must issue a guide for users of ACS data that details the statistical implications of the difference between point-intime and moving average estimates for various uses.
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From page 125... ...
We are optimistic that increased Census Bureau attention to informing data users and stakeholders (whether established users of the longform data or newcomers) about the unique features and challenges of working with ACS data will build a stronger case for the survey.
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From page 126... ...
The role of the ACS is of particular concern; failure to secure commitment to the ACS as a replacement for the census long form would severely impair plans for a shortform-only census and undercut the ability to provide reliable small-area characteristics data by 2010. The Census Bureau should identify the costs and benefits of various approaches to collecting characteristics information if support for the full ACS is not forthcoming.
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From page 127... ...
We strongly encourage the Census Bureau to conduct research that quantifies the sensitivity of ACS-based estimates to fluctuations in sample size, in order to make the case for sustained ACS funding more compelling to policy makers. 4-E.3 Contingency Planning We endorse the ACS and strongly recommend that it replace the long form in the 2010 census.
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From page 128... ...
4-F.1 Group Quarters The intent of the census long form is to provide information on characteristics of the entire population. This means not only the population residing in housing units but also those living in group quarters, such as college dormitories, military barracks, prisons, and medical and nursing facilities.
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From page 129... ...
However, early congressional discussion of the nature and content of the ACS led individual members of Congress to suggest that the ACS be conducted on a voluntary basis. Accordingly, the Census Bureau conducted part of the 2003 Supplementary Survey (the prototype ACS)
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From page 130... ...
] ow-un using the vo~untarv narticination 1 0 J 1 1 ianguage.3 fiche response rates, including item nonresponse rates, on the voluntary surveys were compared with results from those obtained one year earlier in the 2002 Supplementary Survey.
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From page 131... ...
For instance, as the potential basis for an estimate of the poverty rate, the ACS has the advantage of larger sample size but does not cover socioeconomic and poverty-specific questions with the same depth as the CPS. The CPS has the further advantage of years of experience in soliciting detailed economic information; face-to-face interviewers acquire fuller knowledge of the survey content area and may be able to assist CPS respondents in interpreting survey questions in ways that the broader-focus ACS interviewers may not be able to match.
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From page 132... ...
4-F.4 Revisiting Sampling Strategies The basic ACS sampling strategy is simple: each month a systematic sample of approximately 480 of the addresses on the Master Address File is taken, with one-third of mail and telephone nonrespondents randomly chosen for in-person follow-up. A number of variations on this basic strategy are either currently designed or under consideration for later implementation in the ACS by the Census Bureau.
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From page 133... ...
With respect to oversampling of small areas, the Census Bureau intends to use some version of the decennial census longform design. In the 2000 census, sampling rates were 1 in 2 for governmental areas (counties, towns, townships, and school districts)
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From page 134... ...
4-F.5 Interaction with Intercensal Population Estimates and Demographic Analysis Programs One high-priority research area should be the development of models that combine information from other sources such as household surveys, administrative records, census data, and the like with ACS information. One prominent example of this is the interplay of ACS estimates and the Census Bureau's population estimates program.
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From page 135... ...
r' ~ ~ ~ ~ ~ high-priority research area should be identification of better procedures for weighting and imputation, to address nonresponse and undercoverage in the ACS; the hope would be to develop procedures that are, in a sense, optimized for ACS survey data, and not simply borrowed from procedures used on the decennial census long form. lathe methods by which the ACS data could be used to improve demographic analysis could also be applicable to improvements of intercensal population estimates for the nation as a whole (National Research Council, 2000b; Citro, 20004.
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From page 136... ...
However, the use of the ACS in combination with information from various data sourcesincluding census data, data from household surveys, and data from administrative records needs to be a two-way street, as the ACS will provide independent information on population size and various characteristics information formerly obtained from the long form. Specifically with respect to population size, the ACS will produce estimates at the county and major demographic group level that will have relatively large variances for most smaller counties, but because they are independent, they could still be used to improve postcensal population estimates.
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From page 137... ...
in processing the decennial census short and long forms, and because of their resulting recognized benefits and ease of implementation in that very similar setting. Some of these weighting approaches are entirely appropriate for the ACS, and some are unique to the ACS as they are meant to address differential mode effects and the more complex sample design of the ACS relative to the long form.
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From page 138... ...
The particular problem of the treatment of item nonresponse is becoming increasingly important given the degree of nonresponse experienced in the 2000 census.
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