A methodological strategy for a one-number census in the UK

As a result of lessons learnt from the 1991 census, a research programme was set up to seek improvements in census methodology. Underenumeration has been placed top of the agenda in this programme, and every effort is being made to achieve as high a coverage as possible in the 2001 census. In recognition, however, that 100% coverage will never be achieved, the one-number census (ONC) project was established to measure the degree of underenumeration in the 2001 census and, if possible, to adjust fully the outputs from the census for that undercount. A key component of this adjustment process is a census coverage survey (CCS). This paper presents an overview of the ONC project, focusing on the design and analysis methodology for the CCS. It also presents results that allow the reader to evaluate the robustness of this methodology.     

人口普查净误差构成部分的估计

 人口普查误差,即普查登记人数与“人口数真值”之差,也叫净误差,实际上是普查遗漏人数抵消普查错误计数人数的结果。净误差掩盖了人口普查中所发生的错误计数和遗漏这两个方面的错误的真实情况。美国普查局决定,在2010年人口普查的事后质量检查中,除了像以往一样继续估计净误差之外,还将估计错误计数人数和遗漏人数。这是对人口普查事后质量检查工作的一项重大改进。本文在解读有关文献的基础上,讨论了估计错误计数人数和遗漏人数的途径、数据准备以及抽样估计的有关问题。     

An alternative view of the 2001 census and future census taking

Summary.  The 2001 census in the UK asked for a return of people 'usually living at this address'. But this phrase is fuzzy and may have led to undercount. In addition, analysis of the sex ratios in the 2001 census of England and Wales points to a sex bias in the adjustments for net undercount—too few males in relation to females. The Office for National Statistics's abandonment of the method of demographic analysis for the population of working ages has allowed these biases to creep in. The paper presents a demographic account to check on the plausibility of census results. The need to revise preliminary estimates of the national population over a period of years following census day—as experienced in North America and now in the UK—calls into question the feasibility of a one-number census. Looking to the future, the environment for taking a reliable census by conventional methods is deteriorating. The UK Government's proposals for a population register open up the possibility of a Nordic-style administrative record census in the longer term.     

非抽样误差视角下普查涵盖误差及其模型研究

根据普查数据生成过程,将实际普查汇总结果与目标总体真值的净误差定义为普查涵盖误差;从非抽样误差的作用分析,提出涵盖误差来源影响的三个假设,并论证采用净误差表现普查涵盖误差的合理性。在此基础上,将涵盖误差的产生机制和普查数据汇总模型结合,构建不同普查类型下计数与内容涵盖误差的模型与误差分解过程;以此论述了非抽样误差对涵盖误差的影响作用,以及计数涵盖误差和内容涵盖误差间的联系,为进一步研究普查数据质量评估与控制奠定理论基础。     

Proposals for 2001 samples of anonymized records: An assessment of disclosure risk

In 1991 Marsh and co-workers made the case for a sample of anonymized records (SAR) from the 1991 census of population. The case was accepted by the Office for National Statistics (then the Office of Population Censuses and Surveys) and a request was made by the Economic and Social Research Council to purchase the SARs. Two files were released for Great Britain—a 2% sample of individuals and a 1% sample of households. Subsequently similar samples were released for Northern Ireland. Since their release, the files have been heavily used for research and there has been no known breach of confidentiality. There is a considerable demand for similar files from the 2001 census, with specific requests for a larger sample size and lower population threshold for the individual SAR. This paper reassesses the analysis of Marsh and co-workers of the risk of identification of an individual or household in a sample of microdata from the 1991 census and also uses alternative ways of assessing risks with the 1991 SARs. The results of both the reassessment and the new analyses are reassuring and allow us to take the 1991 SARs as a base-line against which to assess proposals for changes to the size and structure of samples from the 2001 census.     

A controlled donor imputation system for a one-number census

Summary. The 2001 UK census was a one-number census. An integral part of such a process has been the creation of a transparent census database that has been adjusted for the underenumeration in the 2001 census. The methodology for creating this database is based on a controlled donor imputation system that imputes individuals and households estimated to have been missed in the census. This paper describes this methodology and provides results from a statistical assessment of its performance using data that realistically simulate the census process.     

中国省域人口总数修订

人口统计数据是制定宏观经济政策和规划人口发展的基础。中国非普查年度人口总数常常与普查年度人口总数差异较大,而关于中国非普查年度人口统计数据修订的研究较少。建立省域人口增长率的固定效应模型,描述中国各省域人口总数的变化趋势,基于拟合模型和普查数据,提出中国省域人口总数修订方法,并对2001年至2009年中国省域人口总数进行修订,结果表明:2001年至2009年中国人口总数修订值与《中国统计年鉴》公布的人口总数之间存在差异,差异率低于0.5%;省域人口总数修订值变化相对平稳,在年度之间的变化幅度相对小,能够更合理反映各省域人口总数的发展趋势。     

Using the 2001 census to study human capital movements affecting Britain's larger cities: insights and issues

Summary.  Human capital is increasingly being recognized as crucial to the sustained growth of British cities, and the population census is unrivalled as a source of data on the characteristics of people moving to and from cities. Taking advantage of new features in the 2001 census, the paper examines how successful 27 of Britain's largest cities and their regions are in maintaining their labour force complement, giving particular attention to young adults and people working in high level occupations. Considerable variation is apparent between city regions, but the interpretation of results is somewhat hampered by limitations in the census data, prompting recommendations for future data collection.     

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."     

The case for small area microdata

Summary.  Census data are available in aggregate form for local areas and, through the samples of anonymized records (SARs), as samples of microdata for households and individuals. In 1991 there were two SAR files: a household file and an individual file. These have a high degree of detail on the census variables but little geographical detail, a situation that will be exacerbated for the 2001 SAR owing to the loss of district level geography on the individual SAR. The paper puts forward the case for an additional sample of microdata, also drawn from the census, that has much greater geographical detail. Small area microdata (SAM) are individual level records with local area identifiers and, to maintain confidentiality, reduced detail on the census variables. Population data from seven local authorities, including rural and urban areas, are used to define prototype samples of SAM. The rationale for SAM is given, with examples that demonstrate the role of local area information in the analysis of census data. Since there is a trade-off between the extent of local detail and the extent of detail on variables that can be made available, the confidentiality risk of SAM is assessed empirically. An indicative specification of the SAM is given, having taken into account the results of the confidentiality analysis.     

Combining census and registration data to estimate detailed elderly migration flows in England and Wales

Summary.  A log-linear model is developed to estimate detailed elderly migration flows by combining data from the 2001 UK census and National Health Services patient register. After showing that the census and National Health Service migration flows can be reasonably combined, elderly migration flows between groupings of local authority districts by age, sex and health status for the 2000–2001 and 2003–2004 periods are estimated and then analysed to show how the patterns have changed. By combining registration data with census data, we can provide recent estimates of detailed elderly migration flows, which can be used for improvements in social planning or policy.     

The trial population census

The author describes the trial population census that was scheduled to take place in the USSR in December 1986 to test methodology, programs, and computational techniques to be used in the 1989 census. The sample for the trial census was 800,000 individuals residing in various parts of the country.     

人口普查误差刍议

许多国家每次人口普查之后都要对其进行质量评估,计算人口普查误差,包括净误差及其构成部分（普查遗漏和普查错误计数）。通常采用先估计净误差,然后估计普查错误计数和普查遗漏。人口普查误差计算的关键是估计总体实际人口数。目前多数国家是使用基于捕获-再捕获模型和事后分层的双系统估计量估计实际人口数。最近1～2年美国提出使用基于罗吉斯蒂回归模型的双系统估计量估计实际人口数。研究结论表明：真正的人口普查误差其实是不能计算的;基于罗吉斯蒂回归模型的双系统估计量由于不受样本量限制而可以选择较多的事后分层变量,因而它优于基于事后分层的双系统估计量。     

Combining census,dual-system,and evaluation study data to estimate population shares

"The 1990 [U.S.] census and Post-Enumeration Survey produced census and dual system estimates (DSE) of population by domain, together with an estimated sampling covariance matrix of the DSE. Estimates of the bias of the DSE were derived from various PES evaluation programs. Of the three sources, the unadjusted census is the least variable but is believed to be the most biased, the DSE is less biased but more variable, and the bias estimates may be regarded as unbiased but are the most variable. This article addresses methods for combining the census, the DSE, and bias estimates obtained from the evaluation programs to produce accurate estimates of population shares, as measured by weighted squared- or absolute-error loss functions applied to estimated population shares of domains."     

Ghettos of the mind: the empirical behaviour of indices of segregation and diversity

Summary.  The effect of immigration on social cohesion is a political issue, expressed as a fear that racially skewed residential patterns represent ghettos which prevent integration. Residential patterns have been measured by indices of segregation. The range of indices is reviewed in the paper and measured empirically for England and Wales by using census data for 1991 and 2001, including a new index of migration dispersal. There has been an increase in residential mixing as a result of growing minority populations and their more even spread across localities. These two trends are identified by two commonly used indices of segregation which are moving in opposite directions for the most recent immigrant groups. The sensitivity of each index to modifiable area boundaries makes them unsuitable for evaluation of cities' relative performance. The residential patterns of cities after immigration are more clearly understood by using demographic measures of migration and age structure.     

Flexible Bivariate Count Data Regression Models

The article develops a semiparametric estimation method for the bivariate count data regression model. We develop a series expansion approach in which dependence between count variables is introduced by means of stochastically related unobserved heterogeneity components, and in which, unlike existing commonly used models, positive as well as negative correlations are allowed. Extensions that accommodate excess zeros, censored data, and multivariate generalizations are also given. Monte Carlo experiments and an empirical application to tobacco use confirms that the model performs well relative to existing bivariate models, in terms of various statistical criteria and in capturing the range of correlation among dependent variables. This article has supplementary materials online.     

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."     

人口普查覆盖误差估计方法综述

人口普查工作的质量主要体现在覆盖误差的规模上.人口统计学家创建了估计人口普查覆盖误差的方法.有些方法利用独立于人口普查本身的信息,另外一些方法则利用人口行政记录的信息.由于每种方法都有其特定的形成背景和适用范围,因而没有适合于所有国家和地区的通用方法.通过对美国、新西兰、澳大利亚、英国和中国的人口普查覆盖误差估计方法进行了较为详细的介绍,说明了这些方法的使用情况.研究表明,任何一种估计方法都有其局限性,需要不断改进与完善.