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)."     

Some coverage error models for census data

"Alternative models are presented for representing coverage error in surveys and censuses of human populations. The models are related to the capture-recapture models used in wildlife applications and to the dual-system models employed in the vital events literature. Estimation methodologies are discussed for one of the coverage error models." After a discussion of the theory underlying the methodology, "distinctions are made between two kinds of error: (a) sampling error and (b) error associated with the model. An example involving data from the 1980 U.S. census is presented. The problem of adjusting census and survey data for coverage error is also discussed."     

An evaluation of population projection errors for census tracts

"In this article we evaluate the accuracy and bias of projections of total population and population by age group for census tracts in three counties in Florida. We use [U.S. census] data from 1970 and 1980 and several simple extrapolation techniques to produce projections for 1990; we then compare these projections with 1990 census counts and evaluate the differences. For the total sample, we find mean absolute errors of 17%-20% for the three most accurate techniques for projecting total population and find no indication of overall bias. For individual age groups, mean absolute errors range from 20%-29%." This is a revised version of a paper presented at the 1993 Annual Meeting of the Population Association of America.     

Evaluation of procedures for improving population estimates for small areas

"We provide and illustrate methods for evaluating across-the-board ratio estimation and synthetic estimation, two techniques that might be used for improving population estimates for small areas. The methods emphasize determination of a break-even accuracy of knowledge concerning externally obtained population totals, which marks the point at which improvement occurs." The techniques are illustrated using 1980 U.S. census data.     

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."     

The USA's bicentennial census: new directions for methodology in 1990

"Planning is under way for the U.S.A. bicentennial census in 1990. The U.S. Census Bureau sponsored a study panel under the U.S. Committee on National Statistics to consider key aspects of methodology for the census and to recommend priority areas for research and testing. The recommendations of the Panel on Decennial Census Methodology, which are summarized in this paper, cover four main topics: adjustment of the census counts for coverage errors, methods of coverage evaluation, uses of sampling in obtaining the count, and uses of administrative records in improving the quality of selected content items."     

Measurement of Hispanic ethnicity in the U.S. census: an evaluation based on latent-class analysis

"Two models, the U.S. census model and the latent-class model, are compared in their application to evaluating measurements of ethnicity. Although the census approach assumes that the response categories of a questionnaire item correspond to groups in the population, the latent-class approach seeks to assess whether any set of response categories can represent observed ethnic heterogeneity. Data collected using the 1990 census Hispanic-origin question and other instruments for measuring ethnicity suggest that the latent-class approach is superior whenever the response categories are not known to be valid. In particular, using the latent-class model, this article rejects the census model's assumption of a single dimension of meaning underlying responses to the Hispanic-origin question."     

Analyses of public use decennial census data with multiply imputed industry and occupation codes

"This paper gives a brief introduction to multiple imputation for handling non-response in surveys. We then describe a recently completed project in which multiple imputation was used to recalibrate industry and occupation codes in 1970 U.S. census public use samples to the 1980 standard. Using analyses of data from the project, we examine the utility of analysing a large data set having imputed values compared with analysing a small data set having true values, and we provide examples of the amount by which variability is underestimated by using just one imputation rather than multiple imputations."     

Federal statistics in a complex environment: the case of the 1980 census

A discussion of the 1980 U.S. census is presented. The authors suggest that the taking of a national census is not just a statistical exercise, but an exercise involving ethics, epistemology, law, and politics. They contend that conducting a national census can be defined as an ill-structured problem in which the various complexities imposed by multidisciplinarity cannot be separated. "The 1980 census is discussed as an ill-structured problem, and a method for treating such problems is presented, within which statistical information is only one component."     

Adjusting the 1980 census of population and housing

"In 1980, several cities and states sued the U.S. Census Bureau to correct census results. This correction would adjust for the differential undercounting of Blacks and Hispanics, especially in cities. In this article, the authors, each of whom testified for New York City and State in their joint lawsuit against the Census Bureau, describe the likely pattern of the undercount and present a method to adjust for it." The authors describe available methods for data adjustment and introduce a regression-based composite method of adjustment, which is used to estimate the undercounts for 66 areas. "As expected, we find that the highest undercount rates are in large cities, and the lowest are in states and state remainders with small percentages of Blacks and Hispanics. Next, we analyze how sensitive our estimates are to changes in data and modeling assumptions. We find that these changes do not affect the estimates very much. Our conclusion is that regardless of whether we use one of the simple methods or the composite method and regardless of how we vary the assumptions of the composite method, an adjustment reliably reduces population shares in states with few minorities and increases the shares of large cities."     

Census data quality--a user's view

"This paper presents the perspective of a major user of both decennial and economic [U.S.] census data. It illustrates how these data are used as a framework for commercial marketing research surveys that measure television audiences and sales of consumer goods through retail stores, drawing on Nielsen's own experience in data collection and evaluation. It reviews Nielsen's analyses of census data quality based, in part, on actual field evaluation of census results. Finally, it suggests ways that data quality might be evaluated and improved to enhance the usefulness of these census programs."     

Survival models for fertility evaluation

"Two proportional hazards models for cohort fertility evaluation are constructed. Time-dependent covariates describe sources of heterogeneity between and within women regarding fertility characteristics. In the first model, U.S. birth rates specific to maternal age, race, parity, and birth cohort are used as underlying hazard rates. Covariate effects are estimated by maximizing the full likelihood. In the second model, covariate effects are estimated via Cox regression with stratified underlying hazard rates regarded as unknown nuisance parameters." The authors illustrate the models "with an evaluation of the fertility histories of the wives of workers at a manufacturing plant with potential for hazardous exposure. Adjustments to the U.S. birth rates for maternal age and parity zero experience are required with the first approach. Then, despite differences in the model-specific estimation procedures, the point estimates of the exposure effect and the estimated standard errors from the two models are practically equivalent."     

A three-sample multiple-recapture approach to census population estimation with heterogeneous catchability

"A central assumption in the standard capture-recapture approach to the estimation of the size of a closed population is the homogeneity of the 'capture' probabilities. In this article we develop an approach that allows for varying susceptibility to capture through individual parameters using a variant of the Rasch model from psychological measurement situations. Our approach requires an additional recapture. In the context of census undercount estimation, this requirement amounts to the use of a second independent sample or alternative data source to be matched with census and Post-Enumeration Survey (PES) data.... We illustrate [our] models and their estimation using data from a 1988 dress-rehearsal study for the 1990 census conducted by the U.S. Bureau of the Census, which explored the use of administrative data as a supplement to the PES. The article includes a discussion of extensions and related models."     

Improving the accuracy of intercensal estimates and postcensal projections of the civilian noninstitutional population: a parameterization of institutional prevalence rates

The authors first note that current official U.S. population estimates and projections are based on the assumption that certain characteristics of the institutionalized population remain constant between censuses. The article "examines the empirical validity of this assumption by using data from the decennial censuses for 1940-1980 and, in light of substantial decade to decade changes in the age patterns of the institutional proportions for sex- and race-specific populations, seeks to develop alternative methods." As part of these alternative methods, "parametric curves are fit to the age-specific institutional proportions for each population for each decade. A study of the observed historical variation in the parameters of these curves then leads to some suggestions about how their shapes can be estimated between censuses and projected beyond the latest available census to provide more accurate estimates and projections of the civilian noninstitutional population." This is a revised version of a paper originally presented at the 1984 Annual Meeting of the Population Association of America (see Population Index, Vol. 50, No. 3, Fall 1984, p. 439).     

Using information from demographic analysis in post-enumeration survey estimation

"Population estimates from the 1990 Post-Enumeration Survey (PES), used to measure decennial census undercount, were obtained from dual system estimates (DSE's) that assumed independence within strata defined by age-race-sex-geography and other variables. We make this independence assumption for females, but develop methods to avoid the independence assumption for males within strata by using national level sex ratios from demographic analysis (DA).... We consider several...alternative DSE's, and use DA results for 1990 to apply them to data from the 1990 U.S. census and PES."     

How increased automation will improve the 1990 census of population and housing of the United States

"The U.S. Bureau of the Census will increase significantly the automation of operations for the 1990 Census of Population and Housing, thus eliminating or reducing many of the labor-intensive clerical operations of past censuses and contributing to the speedier release of data products. An automated address control file will permit the computer to monitor the enumeration status of an address. The automated address file will also make it possible to begin electronic data processing concurrently with data collection, and, thus, 5-7 months earlier than for the 1980 Census. An automated geographic support system will assure consistency between various census geographic products, and computer-generated maps will be possible. Other areas where automation will be introduced or increased are questionnaire editing, coding of written entries on questionnaires, and reporting of progress and cost by field offices."     

Empirical Bayes procedures for stabilizing maps of U.S. cancer mortality rates

"The geographic mapping of age-standardized, cause-specific death rates is a powerful tool for identifying possible etiologic factors, because the spatial distribution of mortality risks can be examined for correlations with the spatial distribution of disease-specific risk factors. This article presents a two-stage empirical Bayes procedure for calculating age-standardized cancer death rates, for use in mapping, which are adjusted for the stochasticity of rates in small area populations. Using the adjusted rates helps isolate and identify spatial patterns in the rates. The model is applied to sex-specific data on U.S. county cancer mortality in the white population for 15 cancer sites for three decades: 1950-1959, 1960-1969, and 1970-1979. Selected results are presented as maps of county death rates for white males."     

Recent work with microcomputers for census processing in developing countries

The use of microcomputers to process census data in developing countries is discussed. Specifically, the authors describe the Integrated Microcomputer Processing System (IMPS) developed by the U.S. Bureau of the Census and focus "on the recent experience of Burkina Faso and Senegal in using microcomputers. A summary is given of the use of IMPS by an increasing number of countries. Additionally, this paper describes the latest enhancements and future plans for IMPS. It concludes with some thoughts on the use of microcomputers in the areas of data collection and processing, as well as in the use and dissemination of census data."     

Using administrative lists to estimate census omissions

"We present a method for estimating omission rates from censuses. Our method is based on the merger of administrative lists, sampling from these lists, and matching against census rolls. We describe the method, present the results of a test in New York City...in 1980, and evalute the results. We compare our proposed method to other procedures for estimating omission rates."