Frames and coverage
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All (58)
All (58) (40 to 50 of 58 results)
- Articles and reports: 12-001-X199500114411Description:
In 1991, Statistics Canada for the first time adjusted the Population Estimates Program for undercoverage in the 1991 Census. The Census coverage studies provided reliable estimates of undercoverage at the provincial level and for national estimates of large age - sex domains. However, the population series required estimates of undercoverage for age - sex domains within each province and territory. Since the direct survey estimates for some of these small domains had large standard errors due to the small sample size in the domain, small area modelling techniques were needed. In order to incorporate the varying degrees of reliability of the direct survey estimates, a regression model utilizing an Empirical Bayes methodology was used to estimate the undercoverage in small domains. A raking ratio procedure was then applied to the undercoverage estimates to preserve consistency with the marginal direct survey estimates. The results of this modelling process are shown along with the estimated reduction in standard errors.
Release date: 1995-06-15 - Articles and reports: 12-001-X199400214422Description:
Dual system estimation (DSE) has been used since 1950 by the U.S. Bureau of Census for coverage evaluation of the decennial census. In the DSE approach, data from a sample is combined with data from the census to estimate census undercount and overcount. DSE relies upon the assumption that individuals in both the census and the sample can be matched perfectly. The unavoidable mismatches and erroneous nonmatches reduce the accuracy of the DSE. This paper reconsiders the DSE approach by relaxing the perfect matching assumption and proposes models to describe two types of matching errors, false matches of nonmatching cases and false nonmatches of matching cases. Methods for estimating population total and census undercount are presented and illustrated using data from 1986 Los Angeles test census and 1990 Decennial Census.
Release date: 1994-12-15 - Articles and reports: 12-001-X199400214425Description:
We present a formal model based sampling solution to the problem of estimating list frame size based on capture-recapture sampling which has been widely used for animal populations and for adjusting the US census. For two incomplete lists it is easy to estimate total frame size using the Lincoln-Petersen estimator. This estimator is model based with a key assumption being independence of the two lists. Once an estimator of the population (frame) size has been obtained it is possible to obtain an estimator of a population total for some characteristic if a sample of units has that characteristic measured. A discussion of the properties of this estimator will be presented. An example where the establishments are fishing boats taking part in an ocean fishery off the Atlantic Coast of the United States is presented. Estimation of frame size and then population totals using a capture-recapture model is likely to have broad application in establishment surveys due to practicality and cost savings but possible biases due to assumption violations need to be considered.
Release date: 1994-12-15 - Articles and reports: 12-001-X199400214426Description:
In the MARS Project (Monitoring Agriculture with Remote Sensing) of the E.C. (European Community), area frames based on a square grid are used for area estimation through ground surveys and high resolution satellite images. These satellite images are useful, though expensive, for area estimation: their use for yield estimation is not yet operational. To fill this gap the sample elements (segments) of the area survey are used as well for sampling farms with a template of points overlaid on the segment. Most often we use a fixed number of points per segment. Farmers are asked to provide global data for the farm, and estimates are computed with a Horvitz-Thompson approach. Major problems include locating farmers and checking for misunderstanding of instructions. Good results are obtained for area and for production of the main crops. Area frames need to be complemented with list frames (multiple frames) to give reliable estimates for livestock.
Release date: 1994-12-15 - Articles and reports: 12-001-X199300214454Description:
This study covers such imperfect frames in which no population unit has been excluded from the frame but an unspecified number of population units may have been included in the list an unspecified number of times each with a separate identification. When the availability of auxiliary information on any unit in the imperfect frame is not assumed, it is established that for estimation of a population ratio or a mean, the mean square errors of estimators based on the imperfect frame are less than those based on the perfect frame for simple random sampling when the sampling fractions of perfect and imperfect frames are the same. For estimation of a population total, however, this is not always true. Also, there are situations in which estimators of a ratio, a mean or a total based on smaller sampling fraction from imperfect frame can have smaller mean square error than those based on a larger sampling fraction from the perfect frame.
Release date: 1993-12-15 - 46. Stratified telephone survey designs ArchivedArticles and reports: 12-001-X199300114472Description:
Two stage random digit dialing procedures as developed by Mitofsky and elaborated by Waksberg are widely used in telephone sampling of the U.S. household population. Current alternative approaches have, relative to this procedure, coverage and cost deficiencies. These deficiencies are addressed through telephone sample designs which use listed number information to improve the cost-efficiency of random digit dialing. The telephone number frame is divided into a stratum in which listed number information is available at the 100-bank level and one for which no such information is available. The efficiencies of various sampling schemes for this stratified design are compared to simple random digit dialing and the Mitofsky-Waksberg technique. Gains in efficiency are demonstrated for nearly all such designs. Simplifying assumptions about the values of population parameters in each stratum are shown to have little overall impact on the estimated efficiency.
Release date: 1993-06-15 - 47. The creation of a residential address register for coverage improvement in the 1991 Canadian census ArchivedArticles and reports: 12-001-X199200114495Description:
The Address Register is a frame of residential addresses for medium and large urban centres covered by Geography Division’s Area Master File (AMF) at Statistics Canada. For British Columbia, the Address Register was extended to include smaller urban population centres as well as some rural areas. The paper provides an historical overview of the project, its objective as a means of reducing undercoverage in the 1991 Census of Canada, its sources and product, the methodology required for its initial production, the proposed post-censal evaluation and prospects for the future.
Release date: 1992-06-15 - Articles and reports: 12-001-X199200114496Description:
The Population Estimates Program of Statistics Canada has traditionally been benchmarked to the most recent census, with no allowance for census coverage error. Because of a significant increase in the level of undercoverage in the 1986 Census, however, Statistics Canada is considering the possibility of adjusting the base population of the estimates program for net census undercoverage. This paper develops and compares four estimators of such a base population: the unadjusted census counts, the adjusted census counts, a preliminary test estimator, and a composite estimator. A generalization of previously-proposed risk functions, known as the Weighted Mean Square Error (WMSE), is used as the basis of comparison. The WMSE applies not only to population totals, but to functions of population totals such as population shares and growth rates between censuses. The use of the WMSE to develop and evaluate small-area estimators in the context of census adjustment is also described.
Release date: 1992-06-15 - 49. Sample design of the 1988 National Farm Survey ArchivedArticles and reports: 12-001-X199000114553Description:
The National Farm Survey is a sample survey which produces annual estimates on a variety of subjects related to agriculture in Canada. The 1988 survey was conducted using a new sample design. This design involved multiple sampling frames and multivariate sampling techniques different from those of the previous design. This article first describes the strategy and methods used to develop the new sample design, then gives details on factors affecting the precision of the estimates. Finally, the performance of the new design is assessed using the 1988 survey results.
Release date: 1990-06-15 - 50. European experience of using administrative data for censuses of population: The policy issues that must be addressed ArchivedArticles and reports: 12-001-X198900114575Description:
The experience of the four Nordic countries illustrates the advantages and disadvantages of a register-based census of population and points to ways in which the disadvantages can be contained. Other countries see major obstacles to a register-based census: the lack of data systems of the kind and quality needed; and public concern about privacy and the power of the State. These issues go far beyond statistics; they concern policy and administration. The paper looks at the situation in two countries, the United Kingdom and Australia. In the United Kingdom past initiatives aimed at population registration in peacetime foundered and the present environment is hostile to any new initiative. But the government is going ahead with a controversial reform of local taxation that involves setting up new registers. In Australia the government tabled a Bill to introduce identity cards and an associated register, and advanced clearcut political arguments to support it; the Bill was later withdrawn. The paper concludes that the issues involved in reforming data systems deserve to be fully discussed and gives reasons why statisticians should take a leading part in the debate.
Release date: 1989-06-15
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Analysis (58)
Analysis (58) (30 to 40 of 58 results)
- Articles and reports: 12-001-X19980024353Description:
This paper studies response errors in the Current Population Survey of the U.S. Bureau of the Census and assesses their impact on the unemployment rates published by the Bureau of Labour Statistics. The measurement of these error rates is obtained from reinterview data, using an extension of the Hui and Walter (1980) procedure for the evaluation of diagnostic tests. Unlike prior studies which assumed that the reconciled reinterview yields the true status, the method estimates the error rates in both interviews. Using these estimated error rates, we show that the misclassification in the original survey creates a cyclical effect on the reported estimated unemployment rates. In particular, the degress of underestimation increases when true unemployment is high. As there was insufficient data to distinguish between a model assuming that the misclassification rates are the same throughout the business cycle, and one that allows the error rates to differ in periods of low, moderate and high unemployment, our findings should be regarded as preliminary. Nonetheless, they indicated that the relationship between the models used to assess the accuracy of diagnostic tests, and those measuring misclassification rates of survey data, deserves further study.
Release date: 1999-01-14 - Articles and reports: 75F0002M1998013Description:
This paper outlines the existing poverty and income measures and summarizes the recent developments of new measures.
Release date: 1998-09-30 - Articles and reports: 12-001-X19980013906Description:
In sample surveys, the units contained in the sampling frame ideally have a one-to-one correspondence with the elements in the target population under study. In many cases, however, the frame has a many-to-many structure. That is, a unit in the frame may be associated with multiple target population elements and a target population element may be associated with multiple frame units. Such was the case in a building characteristics survey in which the frame was a list of street addresses, but the target population was commercial buildings. The frame was messy because a street address corresponded either to a single building, multiple buildings, or part of a building. In this paper, we develop estimators and formulas for their variances in both simple and stratified random sampling designs when the frame has a many-to-many structure.
Release date: 1998-07-31 - Articles and reports: 12-001-X19980013912Description:
Efficient estimates of population size and totals based on information from multiple list frames and an independent area frame are considered. This work is an extension of the methodology proposed by Harley (1962) which considers two general frames. A main disadvantage of list frames is that they are typically incomplete. In this paper, we propose several methods to address frame deficiencies. A joint list-area sampling design incorporates multiple frames and achieves full coverage of the target population. For each combination of frames, we present the appropriate notation, likelihood function, and parameter estimators. Results from a simulation study that compares the various properties of the proposed estimators are also presented.
Release date: 1998-07-31 - 35. Temporary mobility and reporting of usual residence ArchivedArticles and reports: 12-001-X19980013913Description:
Temporary mobility is hypothesized to contribute toward within-household coverage error since it may affect an individual's determination of "usual residence" - a concept commonly applied when listing persons as part of a household-based survey or census. This paper explores a typology of temporary mobility patterns and how they relate to the identification of usual residence. Temporary mobility is defined by the pattern of movement away from, but usually back to a single residence over a two-three month reference period. The typology is constructed using two dimensions: the variety of places visited and the frequency of visits made. Using data from the U.S. Living Situation Survey (LSS) conducted in 1993, four types of temporary mobility patterns are identified. In particular, two groups exhibiting patterns of repeat visit behavior were found to contain more of the types of people who tend to be missed during censuses and surveys. Log-linear modeling indicates spent away and demographic characteristics.
Release date: 1998-07-31 - Articles and reports: 91F0015M1998005Geography: CanadaDescription:
All countries that organize censuses have concerns about data quality and coverage error. Different methods have been developed in evaluating the quality of census data and census undercount. Some methods make use of information independent of the census itself, while some others are designed to check the internal consistency of the data. These are expensive and complicated operations.
Given that the population in each country is organized differently and that the administrative structures differ from one country to another, no universal method can be applied. In order to compare the methods and identify their strengths and gaps, Demography Division of Statistics Canada has reviewed the procedures used in four industrialized countries: the United States, the United Kingdom, Australia and, of course, Canada. It appears from this review that demographic analysis can help considerably in the identification of inconsistencies through comparisons of consecutive censuses, while micro-level record linkage and survey based procedures are essential in order to estimate the number of people omitted or counted twice in census collection. The most important conclusion from this review is that demographers and statisticians have to work together in order to evaluate the figures the accuracy of which will always remain questionable.
Release date: 1998-03-27 - 37. A synthetic, robust and efficient method of making small area population estimates in France ArchivedArticles and reports: 12-001-X19970023620Description:
Since France has no population registers, population censuses are the basis for its socio-demographic information system. However, between two censuses, some data must be updated, in particular at a high level of geographic detail, especially since censuses are tending, for various reasons, to be less frequent. In 1993, the Institut National de la Statistique et des Études Économiques (INSEE) set up a team whose objective was to propose a system to substantially improve the existing mechanism for making small area population estimates. Its task was twofold: to prepare an efficient and robust synthesis of the information available from different administrative sources, and to assemble a sufficient number of "good" sources. The "multi-source" system that it designed, which is reported on here, is flexible and reliable, without being overly complex.
Release date: 1998-03-12 - 38. Statistical process control of sampling frames ArchivedArticles and reports: 12-001-X199500214391Description:
Statistical process control can be used as a quality tool to assure the accuracy of sampling frames that are constructed periodically. Sampling frame sizes are plotted in a control chart to detect special causes of variation. Procedures to identify the appropriate time series (ARIMA) model for serially correlated observations are described. Applications of time series analysis to the construction of control charts are discussed. Data from the United States Department of Labor’s Unemployment Insurance Benefits Quality Control Program is used to illustrate the technique.
Release date: 1995-12-15 - Articles and reports: 12-001-X199500214393Description:
Major uncertainties about the quality of elderly population and death enumerations in the United States result from coverage and content errors in the censuses and the death registration system. This study evaluates the consistency of reported data between the two sources for the white and the African-American populations. The focus is on the older population (aged 60 and above), where mortality trends have the greatest impact on social programs and where data are most problematic. Using intercensal cohort analysis, age-specific inconsistencies between the sources are identified for two periods: 1970-1980 and 1980-1990. The U.S. data inconsistencies are examined in light of evidence in the literature regarding the nature of coverage and content errors in the data sources. Data for African-Americans are highly inconsistent in the 1970-1990 period, likely the result of age overstatement in censuses relative to death registration. Inconsistencies also exist for whites in the 1970-1980 intercensal period. We argue that the primary source of this error is an undercount in the 1970 census relative to both the 1980 census and the death registration. In contrast, the 1980-1990 data for whites, and particularly for white females, are highly consistent, far better than in most European countries.
Release date: 1995-12-15 - 40. Between-state heterogeneity of undercount rates and surrogate variables in the 1990 U.S. census ArchivedArticles and reports: 12-001-X199500114410Description:
As part of the decision on adjustment of the 1990 Decennial Census, the U.S. Census Bureau investigated possible heterogeneity of undercount rates between parts of different states falling in the same adjustment cell or poststratum. Five “surrogate variables” believed to be associated with undercount were analyzed using a large extract from the census and significant heterogeneity was found. Analysis of Post Enumeration Survey on undercount rates showed that more variance was explained by poststratification variables than by state, supporting the decision to use the poststratum as the adjustment cell. Significant interstate heterogeneity was found in 19 out of 99 poststratum groups (mainly in nonurban areas), but there was little if any evidence that the poststratified estimator was biased against particular states after aggregating across poststrata. Nonetheless, this issue should be addressed in future coverage evaluation studies.
Release date: 1995-06-15
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