number of returns obtained for occupied units in nonresponse and coverage improvement follow-up (see Moul, 2002, 2003). Hence, although we cannot be sure, it is possible that the speedier completion of nonresponse follow-up in 2000 helped reduce erroneous enumerations.

Intensive analysis of the Accuracy and Coverage Evaluation (A.C.E.) data demonstrated a large number of duplicate enumerations in 2000 (see Chapter 6), which could have been partly due to errors in follow-up processes. Research on the effects of both nonresponse follow-up and coverage improvement follow-up on correct versus erroneous enumerations would be useful.

One evaluation of both the nonresponse follow-up and coverage improvement follow-up efforts in 2000 found that enumerator returns included higher percentages of traditionally hard-to-count groups (children, renters, minorities) compared with mail returns (Moul, 2003:Tables 18–22). Therefore, as was also true in 1990, these operations were important for helping to narrow differences in net undercount rates among groups. Thus, for household members enumerated in 2000:

• 45 percent of nonresponse and coverage improvement enumerations were of people living in rented units, compared with 25 percent renters on mail returns;

• 51 percent of nonresponse and coverage improvement enumerations were of men, compared with 48 percent men on mail returns;

• 59 and 57 percent of nonresponse and coverage improvement enumerations, respectively, were of people under age 35, compared with 45 percent people under age 35 on mail returns;

• 18 percent of nonresponse and coverage improvement enumerations were of Hispanics, compared with 12 percent Hispanics on mail returns;

• 18 and 17 percent of nonresponse and coverage improvement enumerations, respectively, were of blacks, compared with 10 percent blacks on mail returns.