tions and comparisons of adjusted and unadjusted census counts for different levels of geography (Hogan, 2000c). The A.C.E. evaluations covered rates of noninterviews in the independent P-sample and missing data in the P-sample and E-sample; quality control of the matching process; the extent of imputation required for unresolved residence, match, and enumeration status; inconsistent assignment of sample cases to poststrata in the two samples; and variance due to sampling and imputation error in the DSE estimates. The census evaluations covered mail return rates; quality assurance of enumerators’ field work; results of unduplication operations; and extent of missing data. Comparisons with 1990 census data were included when feasible. It was hoped that these assessments, which largely addressed how well operations were performed, would provide sufficient information to conclude that adjusted counts did or did not improve the counts from the census process. In addition, the Census Bureau planned to take account of population estimates from demographic analysis, which historically had provided a comparison standard for the census.

What, then, were the reasons for the decision not to adjust? An important reason cited by the ESCAP report (Executive Steering Committee for A.C.E. Policy, 2001c) was the inconsistencies between the population estimates from the census, the A.C.E., and demographic analysis; those inconsistencies could not be resolved or explained with the available evaluation data within the time available for the decision.

The A.C.E. estimated as of March 2001 that the overall net undercount was only 1.2 percent of the population in 2000 (see Table 5.1)—a decrease from the revised PES estimate of a 1.6 percent net undercount in 1990. However, demographic analysis suggested that the undercount had been reduced even more than was estimated by the A.C.E. The Census Bureau’s initial demographic analysis estimate (as of January 2001) indicated that the 2000 census resulted in a slight (0.7 percent) net overcount of the population and that the A.C.E. overstated the population by even more. Even when the Bureau adjusted the demographic analysis estimate upward in March 2001 to allow for a larger number of undocumented immigrants than were part of the base estimate, the alternate demographic analysis estimate of the 2000 net undercount was only 0.3 percent of the population (Table 5.1).