additional information, however, about the numbers and sources of census omissions.
Documentation for the original A.C.E. estimates (March 2001), the preliminary revised estimates (October 2001), and the A.C.E. Revision II estimates (March 2003) was timely, comprehensive, and thorough.
Finding 6.3: We support the Census Bureau’s decision not to use the March 2003 Revision II A.C.E. coverage measurement results to adjust the 2000 census base counts for the Bureau’s postcensal population estimates program. The Revision II 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 to correct the original estimate of nonmatches 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 (poststrata) for estimating erroneous census enumerations and census omissions. In addition, there is a large discrepancy in coverage estimates for children ages 0–9 when comparing demographic analysis estimates with Revision II A.C.E. estimates (2.6 percent undercount and 0.4 percent net overcount, respectively).
Finding 6.4: Demographic analysis helped identify possible coverage problems in the 2000 census and in the A.C.E. at the national level for a limited set of population groups. However, there are sufficient uncertainties in the revised estimates of net immigration (particularly the illegal component) and the revised assumption of completeness of birth registration after 1984, compounded by the