Procedures To Adjust 1980 Census Counts Have Limitations

GGD-81-28: Published: Dec 24, 1980. Publicly Released: Dec 24, 1980.

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The number of congressional representatives a state receives, as well as district boundaries, are determined by a decennial census. A number of communities, contending that the 1980 census has missed large numbers of persons and that this undercounting will result in their citizens being shortchanged in political representations and federal fund distributions, have taken legal action to have the census count adjusted for the undercount. The Census Bureau dropped a postenumeration survey for estimating 1980 census errors at subnational levels, so that preliminary estimates would be available sooner. GAO reported on the Census Bureau's ability to develop accurate undercount estimates for subnational levels and the effect of dropping a planned post-census survey on the prospects for developing accurate undercount estimates.

Estimates of census errors at subnational levels are needed for correcting census data. Statistical analysis might help in estimating census error at subnational levels. To date, however, the agency had not set up a formal program of applied research for this purpose. The Bureau has primarily used two coverage evaluation techniques, the demographic method and matching studies. These techniques, as implemented by the Bureau, do not provide estimates at geographical levels compatible with census data user needs. The demographic method suffers from limited data, notably the absence of reliable estimates for the size of certain age groups and for the number of illegal aliens. Matching studies, both reinterview studies and reverse record checks, involve the comparison of a list of sample persons or households to the census. Matching techniques have major weaknesses. People tend to respond to a reinterview study in the same way they do to census enumeration. Persons missed by the census are likely to be missed by the reinterview study, and incomplete or invalid data prevent the Bureau from resolving whether a person has been omitted from the census. Matching is a time consuming process because it requires manual case-by-case comparison. Although other statistical methods of analysis for estimating coverage are available, the Bureau has made little use of them. In many communities, an increase in their census count will not proportionately increase their share of federal funds.

Matter for Congressional Consideration

  1. Status: Closed

    Comments: Please call 202/512-6100 for additional information.

    Matter: Congress should enact legislation requiring that the Secretary of Commerce submit a report to the appropriate congressional committees having jurisdiction over the census, 18 months prior to each census, on whether and how he intends to prepare credible estimates of over/undercount at subnational levels, including characteristics for the undercounted persons. The report should include the cost and time needed to make these estimates and an independent assessment of the Bureau's proposed methods.

Recommendations for Executive Action

  1. Status: Closed

    Comments: Please call 202/512-6100 for additional information.

    Recommendation: The Secretary of Commerce should require for future censuses: (1) that the Director of the Bureau of the Census determine the feasibility of providing credible estimates of over/undercounts and distributing them to needed user levels, and if feasible prepare detailed information to describe the methods to be used, including the expected reliability of such estimates as well as the time and costs needed for these efforts; and (2) an independent assessment of the Bureau's proposed methods be made.

    Agency Affected: Department of Commerce

  2. Status: Closed

    Comments: Please call 202/512-6100 for additional information.

    Recommendation: The Secretary of Commerce should require that the Director of the Bureau of the Census organize a program of experiments using statistical analysis to determine whether improved estimates can be developed of the true population at state and substate levels.

    Agency Affected: Department of Commerce

 

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