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At least 19 recordsLinked to original sources
PubMed1996

Census undercount and the undercount of the Black population.

"Despite the [U.S.] Census Bureau's great efforts in various accuracy-improvement and outreach programs, census undercount still persists.... This paper focuses on the undercount of the Black population and its impacts in the form of such biased statistics on Blacks as inflated proportions of Black female-headed households, deflated victimization rates of Black males, or crude death rates of Blacks. The paper concludes with suggestions on how to deal with the undercount problems."

Black or African American↗
PubMed1998

"Appearing twin": undercounting of multiple gestations on early first trimester sonograms.

An important role of first trimester sonography is to determine whether a pregnancy is a singleton, twin, or higher order multiple gestation. We assessed how frequently sonography at 5.0-5.9 weeks undercounts multiple gestations. We identified all pregnancies at our institution since 1988 in which (1) an initial sonogram obtained at 5.0-5.9 weeks demonstrated at least a singleton intrauterine pregnancy and (2) a subsequent sonogram at 6.0 weeks or beyond demonstrated a living multiple gestation. Twenty-four (11%) of 213 dichorionic twin gestations were initially undercounted as singletons, as were six (86%) of seven monochorionic twin gestations. Among 105 higher order multiples, 17 (16%) were undercounted initially. All but one of the undercounted cases were scanned transvaginally. Undercounting occurred in both natural and assisted conceptions, and it occurred more frequently on sonograms obtained at 5.0-5.4 weeks than at 5.5-5.9 weeks (P = 0.02, Fisher's exact test). Prognosis for undercounted multiple gestations was similar to that of correctly counted ones with respect to several measures of pregnancy outcome, including the likelihood that all fetuses would be delivered liveborn, gestational age at birth, and birth weight (P > 0.20, all comparisons). In conclusion, transvaginal sonography at 5.0-5.9 weeks frequently undercounts multiple gestations. Initially undercounted multiple gestations and those correctly counted have similar pregnancy outcomes.

Diagnostic Errors↗
PubMed1982

The census undercount: effects on federal aid to cities.

The impact of adjusting 1980 U.S. population census figures for the undercount on federal grant allocations to cities is examined. In contrast to claims by local officials that their cities have lost up to 200 dollars per uncounted person in federal grants, the authors suggest that an undercount adjustment "could be expected to add little more than [20 dollars] per uncounted person in a few large cities--with most large cities experiencing much smaller gains or even federal aid losses after an adjustment." Several reasons for this finding are discussed. "They relate to the significant limitations of available techniques for estimating the census undercount; the fact that population data are not used in all formula allocation systems; the varied ways in which population data can affect formula allocation systems when they are used; and [the] assumption that federal aid funds would not increase in proportion to the population added as part of an undercount adjustment procedure for federal grants."

Americas↗
PubMed1991

The effects of census undercount adjustment on congressional apportionment.

"This article shows that undercount adjustment [of the 1990 U.S. census] will probably reallocate one [in] three House seats across the states. The adjustment's impact may depend on the method used and the assumptions underlying undercount estimates. Using regression analysis to reduce sampling error in undercount estimates from dual-systems analysis, however, eliminates sensitivity to all but the most extreme changes in assumptions. Generally, adjustment will more likely affect large states than small ones, and large states with proportionately many urban Black and Hispanic residents will likely gain seats at the expense of large states with few such residents."

Americas↗
PubMed1989

Empirical Bayes estimation of undercount in the decennial census.

Empirical Bayes methods are used to estimate the extent of the undercount at the local level in the 1980 U.S. census. "Grouping of like subareas from areas such as states, counties, and so on into strata is a useful way of reducing the variance of undercount estimators. By modeling the subareas within a stratum to have a common mean and variances inversely proportional to their census counts, and by taking into account sampling of the areas (e.g., by dual-system estimation), empirical Bayes estimators that compromise between the (weighted) stratum average and the sample value can be constructed. The amount of compromise is shown to depend on the relative importance of stratum variance to sampling variance. These estimators are evaluated at the state level (51 states, including Washington, D.C.) and stratified on race/ethnicity (3 strata) using data from the 1980 postenumeration survey (PEP 3-8, for the noninstitutional population)."

Americas↗
PubMed1993

Accuracy of the 1990 census and undercount adjustments.

"In July 1991 the [U.S.] Census Bureau recommended to its parent agency, the Department of Commerce, that the 1990 census be adjusted for undercount. The Secretary of Commerce decided not to adjust, however. Those decisions relied at least partly on the Census Bureau's analyses of the accuracy of the census and of the proposed undercount adjustments based on the Post-Enumeration Survey (PES).... This article describes the total error analysis and loss function analysis of the Census Bureau. In its decision not to adjust the census, the Department of Commerce cited different criteria than aggregate loss functions. Those criteria are identified and discussed."

Americas↗
PubMed1988

On estimating census undercount in small areas.

"Net undercount rates in the U.S. decennial census have been steadily declining over the last several censuses. Differential undercounts among race groups and geographic areas, however, appear to persist. In the following, we examine and compare several methodologies for providing small area estimates of census coverage by constructing artificial populations. Measures of performance are also introduced to assess the various small area estimates. Synthetic estimation in combination with regression modelling provide the best results over the methods considered. Sampling error effects are also simulated. The results form the basis for determining coverage evaluation survey small area estimates of the 1900 decennial census."

Americas↗
PubMed1989

[Correcting for an undercount. The case of the U.S. census].

Undercount problems in the U.S. census are outlined, and methods to correct them are described. "Methods tested in the last decade appeared very promising, but a political decision was made not to adjust the census. That decision has now been repealed and the 1990 U.S. Census may be the first to reflect an adjustment for the undercount." (SUMMARY IN ENG AND SPA)

Americas↗
PubMed1984

Report of the ASA Technical Panel on the Census Undercount.

"This report contains recommendations reflecting the views of the ASA Technical Panel on the Census Undercount concerning [U.S.] Census Bureau procedures and plans in the fall of 1982." The report consists of technical statistical advice on measurement and estimation problems. A response by Barbara A. Bailar, reflecting the views of the U.S. Census Bureau, is also included (pp. 257-60).

Americas↗
PubMed1986

Inhibition of esterase activity and an undercounting of circulating monocytes in a population of production workers.

A cross-sectional review of routine employee health status examinations has identified an undercounting of circulating monocytes associated with an inhibition of a surface monocyte esterase, alpha-naphthyl butyrate esterase. It is postulated that this inhibition is associated with an organophosphate used in the production process. Correlation with routine measures of health status are presented.

Adult↗
PubMed1993

Hierarchical logistic regression models for imputation of unresolved enumeration status in undercount estimation.

"In this article we describe a logistic regression modeling approach for nonresponse in the [U.S.] Post-Enumeration Survey (PES) that has desirable theoretical properties and that has performed well in practice.... In the 1990 PES, interviews were not obtained from approximately 1.2% of households in the sample, and approximately 2.1% of the individuals in interviewed households were considered unresolved after follow-up....The missing binary enumeration statuses for these unresolved cases were replaced with probabilities estimated under a statistical model that incorporated covariate information observed for these cases. This article describes an approach to modeling missing binary outcomes when there are a large number of covariates."

Americas↗
PubMed2000

Undercounting features and missing features: evidence for a high-level deficit in strabismic amblyopia.

Abnormal visual development in strabismic amblyopia drastically affects visual perception and properties of neurons in primary visual cortex (V1). To test the notion that amblyopia also has consequences for higher visual areas, we asked humans with amblyopia to count briefly presented features. Using the amblyopic eye, strabismic amblyopes counted inaccurately, markedly underestimating the number of features. This inaccuracy was not due to low-level considerations (blur, visibility, crowding, undersampling or topographical jitter), as they also underestimated the number of features missing from a uniform grid. Rather, counting deficits in strabismic amblyopes reflected a higher-level limitation in the number of features the amblyopic visual system can individuate.

Adult↗
PubMed2001

Undercounts and overstatements: will the IOM report on lesbian health improve research?

In January 1999, the Institute of Medicine (IOM) released a report on lesbian health research that fulfills 3 goals: it provides an extensive review of much of the research that has been done on the health of women who have sex with other women, it addresses the methodological and ethical issues inherent in conducting research on this population, and it suggests avenues for further research. This report will likely help lesbian health researchers gain funding, publish further research in medical journals, and receive support and validation from medical and research institutions. To ensure that such research is useful, benefits the lesbian community, and expands the understanding of lesbian health conditions, particular attention needs to be paid to the methods and definitions used and to the involvement of the lesbian community in designing, implementing, and analyzing the research itself.

Community Health Planning↗