At this point, it seems appropriate to note the importance of the ACS as a potential source of information for any or all of the individual population groups of interest. Each is identified, recorded, and entered on the ACS data file. If, as expected, the ACS becomes operational in 2003, it will completely -- and virtually immediately—obviate any need for "other" sources of information for those characteristics regularly included in the ACS as core items. To the extent that the ACS also includes periodic, supplementary modules covering the full ACS sample, those data will provide ample sample sizes for each of the population subgroups of interest. Finally, if the need for specialized data exists and cannot be met by any of the approaches described in this report, the ACS lends itself as an efficient and timely source of sample for the subpopulations to be included in a new inquiry, either through supplementary questions added to the core, or the inclusion of a full module in one or more months of interviewing. If those approaches prove infeasible, a separate inquiry can be initiated, using a recent sample previously included in the ACS.
The U.S. Census Bureau has strict confidentiality rules, and it will be difficult, if not impossible, for other statistical agencies to gain access to names and addresses in the ACS. The U.S. Census Bureau has stated that, under its authorizing legislation (Title 13, U.S.C.), it cannot legally make available any personal information collected under Census authority, including names or addresses. In effect, this means that only the U.S. Census Bureau can conduct the interviews (or carry out the measurements) for which the ACS provides a sampling frame. Thus, in attempting to supplement samples for existing inquiries, the statistical agencies responsible for the various surveys will have to decide whether joint responsibility—one contractor conducting most of a survey and the U.S. Census Bureau carrying the same functions for the sample supplement—is operationally feasible.
1 "Evaluation of Design Options in HHANES '97," report prepared by Westat, May 31, 1994.
2 "Geographic Oversampling in Demographic Surveys of the U.S.," report reppared by Westat, May 31, 1994
3 Estimation in the Southwest Component of the Hispanic Health and Nutrition Examination Survey," 1982-84, by Gonzalez, Ezzati, Lago, and Waksberg, Proceedings of the SRMS of the American Statistical Association, 1985.