and item nonresponse rates in the P-sample and E-sample, but also for household composition to be accurately reported. Two factors are critical to accurate reporting: first, the ability of the A.C.E. questionnaires and interviewing procedures for P-sample interviewing and follow-up of nonmatched P-sample and E-sample cases to elicit the Census Day residence status of household members; and, second, the willingness of respondents to answer the questions as they were intended.
As an example, a household in the census that was part of the E-sample may have claimed a college student or an institutionalized family member as a household member even though the person was enumerated in his or her group quarters according to census residence rules. The result would be a duplicate census enumeration. In the case when the household was missed by the P-sample, the matching and follow-up process should have identified the nonduplicated E-sample household residents as correct (nonmatched) enumerations and the duplicated college student as having been erroneously enumerated at the household address in the census. If, however, the household persisted in claiming the student as a household member, then the A.C.E. would incorrectly classify him or her as a correct (nonmatched) enumeration, thereby overstating the correct enumeration rate and the DSE estimate of the population. This example and one other involving undetected duplicates of census enumerations with nonmatched P-sample cases are described, along with their effects, in Box 6.1.
The A.C.E. questionnaires were improved over the PES questionnaires, and computer-assisted interviewing ensured that interviewers asked all of the questions as they were written. However, Census Bureau staff worried that the A.C.E. interviewing might not have ascertained Census Day household membership accurately in many cases because the original A.C.E. estimated only 4.6 million duplicate and “other residence” erroneous enumerations whereas the PES estimated 10.7 million of these types of erroneous enumerations (see Anderson and Fienberg, 2001:Table 2). Indeed, the Evaluation Follow-Up and Person Duplication Studies conducted by the Census Bureau in summer 2001 provided evidence that the A.C.E. failed to detect numerous instances in which census respondents listed one or more residents who should not have been counted as part of the household on Census Day. Consequently, the original