net undercount rates, some groups (e.g., black men and renters) continued to be undercounted in 2000.
Finding 6.6: Two factors that contributed to the estimated reductions in net undercount rates in 2000 from 1990 were the large numbers of whole-person imputations and duplicate census enumerations, many of which were not identified in the original (March 2001) A.C.E. estimates. Contributing to duplication were problems in developing the Master Address File and respondent confusion about or misinterpretation of census “usual residence” rules, which resulted in duplication of household members with two homes and people who were enumerated at home and in group quarters.
The complexities of the original A.C.E. and Revision II reestimation and the uncertainties about what the Revision II results tell us about net and gross coverage errors in the 2000 census could lead policy makers to question the value of an A.C.E.-type coverage evaluation program for the 2010 census. To the contrary, we recommend that research and development for the 2010 census give priority to improving an A.C.E.-type coverage evaluation mechanism and that it be implemented in 2010.
Without the 2000 original A.C.E. and Revision II estimation, we would not have acquired so much valuable information about strengths and weaknesses of the 2000 census. In particular, differences between the census counts, the original A.C.E., and the original demographic analysis estimates spurred the development of innovative methods for identifying duplicate census enumerations. These differences also motivated a reexamination of assumptions about immigration estimates in demographic analysis.
The plans for the 2010 census include the serious possibility that the matching methods used in the Further Study of Person Duplication would be used as part of the enumeration process, so that