The A.C.E. included a new operation to match P-sample and January 2000 MAF housing units prior to interviewing. The purpose of the match was to facilitate such operations as large block subsampling, telephone interviewing, and matching. Although the P-sample and census address lists were linked, independence was maintained because no changes were carried over from one list to the other as a consequence of the match.
The A.C.E. used computer-assisted telephone and personal interviewing (CATI/CAPI) to facilitate the accuracy of the information collected and the speed of data capture and processing. The PES used paper-and-pencil methods throughout. The first wave of A.C.E. interviewing began in late April 2000, using the telephone to contact mail return households that provided a telephone number on their census questionnaire and for which there was a clear city-style address. Fully 29 percent of the P-sample household interviews were obtained by telephone. The second wave of interviewing was in person; it began in mid-June and was completed in August, well ahead of the timing achieved in 1990.
The A.C.E. clerical matching operation, which followed a computer match, was conducted by clerks examining computerized P-sample responses and questionnaire images for census cases in the sampled block clusters. The technology was designed to be user-friendly. Because of complete computerization of the operation, all matching could be done at one location, instead of seven as in 1990.
A major change from 1990 was the treatment of movers. The goal of the 1990 PES was to visit each P-sample address and find out where the current residents usually lived as of Census Day (PES-B). The original design for Integrated Coverage Measurement for 2000 ruled out PES-B because of the plan to use sampling for nonresponse