The 2000 Census Interim Assessment (2001) / Chapter Skim
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7. Accuracy and Coverage Evaluation: Assessment
7. Accuracy and Coverage Evaluation: Assessment
Pages 103-130
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From page 103... ...
We consider nine separate aspects of the A.C.E.: · conduct and timing; · household noninterviews in the P-sample; · imputation for missing characteristics and unresolved residence, match, and enumeration status; · quality of matching; · the targeted extended search; · post-stratification; · variance estimates: · final match codes and rates; and · gross errors. We end this chapter with our summary assessment of the A.C.E.
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From page 104... ...
The lower interview rate for Census Day households is due largely to the fact that households that had been occupied entirely by outmovers at the time of the census were harder to interview than other households. This result is not surprising because the new occupants of such households may know nothing of the people who lived there before, and it may not always be possible to interview a knowledgeable neighbor or landlord.
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From page 105... ...
Such cases were retained in both the E- and the P-samples; in the E-sample they were coded as erroneous enumerations and in the P-sample they were not yet assigned a final match status. After all matching and follow-up had been completed, the next step was item imputation.
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From page 106... ...
P-sample imputation rates includes nonmovers, removers, and outmovers, including people who were subsequently removed Tom the sample as nonresidents on Census Day. Excluded Tom the base for the A.C.E.
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From page 107... ...
. The reason is because the P-sample and E-sample imputations were performed using somewhat different procedures; also, imputation procedures for the P-sample were carried out separately for each characteristic.3 Unresolved Residence, Match, and Enumeration Status Residence Status The weighted percentage of all P-sample nonmover and outmover cases with unresolved Census Day residence status was 2.2 percent, of which 51.7 percent were cases lacking enough reported information for matching.
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From page 108... ...
The eight match status groups discriminated well: for example, residence probabilities were very low for potentially fictitious people or people said to be living elsewhere on Census Day (14%~;5 moderate for college and military age children in partially matched households (84%~; and very high for cases resolved 40ne would not expect there to be confirmed non-Census Day residents or unresolved cases among nonmovers and outmovers; however, it could happen because mover status was assigned prior to field follow-up work. 5 Fictitious people are those for whom it seems clear that the data were fabricated by the respondent or enumerator (e.g., a return for Mickey Mouse.)
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From page 109... ...
After imputation, the percentage of correct enumerations dropped slightly, from 95.5 percent of resolved cases (correct and erroneous enumerations) to 6 The denominator for the percentage is P-sample nonmovers and outmovers who were confirmed Census Day residents or had unresolved residence status; confirmed non-Census Day residents were dropped from the P-sample at this point.
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From page 110... ...
enumerations were in fact erroneous, then the estimated correct enumeration rate will be too high and the estimate of the DSE will be too high. It is not possible to assess the reliability of assignment of the final match codes until the Census Bureau publishes results from evaluation studies that involve rematching and verifying samples of A.C.E.
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From page 111... ...
As indirect indicators of the quality of the matching, we examined specific match codes and how they related to the various steps in the process. Extent of Checking Required to Confirm Final Match Code We looked first at final match codes and asked what proportion of the cases in each category were confirmed at the conclusion of computer matching, at the conclusion of clerical matching, or not until after field follow-up.
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From page 113... ...
, although 69 percent of final confirmed nonmatches for American Indians and Alaska Natives were not declared a nonmatch until after being checked in the field, compared with only 47 percent for non-Hispanic whites and other races. How many nonmatches were correctly assigned and how many should have been identified as either matches or cases to be dropped from the P-sample (e.g., fictitious cases or people residing elsewhere on Census Day)
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From page 114... ...
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From page 115... ...
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From page 116... ...
In a sample of block clusters for which there was reason to expect geocoding errors (2,177 of 6,414 such clusters) , the clerical search for matches of P-sample and census enumerations and for correct E-sample enumerations was extended to one ring of blocks surrounding the A.C.E.
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From page 117... ...
block cluster because there was no corresponding census address, then a search for a match in the surrounding ring would likely be successful. The Census Bureau has fielded a study to determine if P-sample address geocoding errors largely explain the larger increase in the match rate compared with the erroneous enumeration rate.
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From page 118... ...
The Census Bureau has fielded a study to determine the accuracy of the identification of Esample units that were eligible for TES. The Bureau is also studying possible discrepancies between the classification of erroneous E-sample housing units in the housing unit match and the classification of some of the people in those units during field follow-up as correct enumerations.
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From page 119... ...
By race/ethnicity domain, inconsistent cases as a percentage of E-sample matches ranged from 1.5 percent for American Indians and Alaska Natives on reservations to 18.3 percent for Native Hawaiians and Pacific Islanders to 35.7 percent for American Indians and Alaska Natives off reservations. By age and sex, the percentage of inconsistent cases among American Indians and Alaska Natives off reservations ranged from 54 percent for nonowner females aged 18-29 to 68 percent for nonowner males aged 50 or older.
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From page 121... ...
After the household noninterview adjustment for Census Day, 90 percent of the weights were between 49 and i°The variance estimates developed by the Census Bureau likely underestimate the true variance, but the extent of underestimation is not known. The variance estimation excludes some minor sources of error (specifically, the large block subsampling and the P-sample noninterview adjustment)
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From page 123... ...
Final Match and Enumeration Status P-Sample Match Codes The distribution of final match codes for the P-sample was 89.5 percent confirmed match, 7.4 percent confirmed nonmatch, 2.2 percent match or residence status unresolved, and 0.9 percent not a Census Day resident or removed for another reason (e.g., a fictitious or duplicate P-sample case)
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From page 124... ...
SOURCES: A.C.E. match codes are Tom tabulations by panel staff of P-sample cases who went through the matching process, weighted using TESFINWT and excluding TES-eligible people not In TES sample block clusters (who have zero TESFINWT)
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From page 125... ...
After imputation for enumeration status, the overall E-sample correct enumeration rate (matches and other correct enumerations divided by those groups plus erroneous enumerations) was 95.3 percent.
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From page 127... ...
It is important to take note of gross errors, however, because higher or lower net undercount does not relate directly to the level of gross errors. There can be a zero net undercount and a high rate of gross omissions and gross erroneous enumerations.
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From page 128... ...
to gross erroneous enumerations. a The alternative estimates of erroneous enumerations In 2000 are not consistent with the information on types of erroneous enumerations above.
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From page 129... ...
showed similar, but less pronounced, patterns of net undercount than the 1990 PES. Given that P-sample match rates and Esample erroneous enumeration rates were similar between the A.C.E.
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From page 130... ...
Not only were addresses added from each stage of census field operations, they were deleted in an effort to minimize duplicate and erroneous entries. In total, the Census Bureau estimates that about 4 million addresses were added to the MAP during census field operations 2.3 million addresses during questionnaire delivery in update/leave, update/enumerate, and listlenumerate areas (see "Questionnaire Delivery and Mail Return," below)
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