roneous enumerations and omissions were almost as high as in 1990. The distribution of coverage errors across geographic areas is hard to discern from the available information; there is no information about coverage of group quarters residents.
In March 2001, October 2001, and March 2003, the Census Bureau announced that it would not adjust the 2000 census results for incomplete coverage of some population groups (and overcounting of other groups). In the panel’s view, all three decisions are justified. The Bureau’s March 2001 and October 2001 decisions are justified given: (1) its conclusion in March that evaluation studies were not sufficient to determine the accuracy of the A.C.E. population estimates and (2) its conclusion in October, after further study, that the original A.C.E. population estimates were too high. The Bureau’s March 2003 decision not to use the A.C.E. Revision II coverage measurement results to adjust the 2000 census base counts for the Bureau’s postcensal population estimates program is justified as well. Although the Revision II estimation work was thorough, innovative, and of high quality, the results are too uncertain to be used with sufficient confidence about their reliability for adjustment of census counts for subnational geographic areas and population groups.
Sources of uncertainty stem from the small samples of the A.C.E. data that were available to correct components of the original A.C.E. estimates of erroneous enumerations and non-A.C.E. residents and the consequent inability to make these corrections for other than very large population groups; the inability to determine which of each pair of duplicates detected in the A.C.E. evaluations was correct and which should not have been counted in the census or included as an A.C.E. resident; the possible errors in subnational estimates from the choice of one of several alternative “correlation bias” adjustments to compensate for higher proportions of missing men relative to women; the inability to make correlation bias adjustments for population groups other than blacks and nonblacks; and the possible errors for some small areas from the use of different population groups for estimating erroneous census enumerations and census omissions.