Forecasting obesity trends in England

Summary.  Forecasts of trends in obesity in England for 2010 are produced by treating the available data, which contain the proportions of the population, categorized by age and sex, falling into different body mass index ranges, as compositional data sets, so that the implicit simplex restrictions are automatically satisfied. Forecasts are calculated by using linear trend models for the log-ratio transformations and are accompanied by prediction regions. The advantages of treating data on proportions compositionally are emphasized and compared with forecasts that have been obtained by ignoring this restriction.     

Tobacco: public perceptions and the role of the industry

Summary. The paper briefly examines the substantial risks of smoking, and how people's perception of them may be influenced by tobacco control policy and by the activities of the tobacco industry. The comparative lack of effectiveness of the self-regulation system of implementing tobacco control policy is noted, illustrated by the example of cigarette pack health warnings, from the first examples under the voluntary system to the significantly more robust and effective pictorial warnings system pioneered by Canada and implemented by legislation, similar to measures recently approved by the European Union. Other aspects of tobacco control policy are discussed, including health education, restricting the promotion of tobacco and changing the social acceptability of smoking. Three areas of success in the UK—taxation, the leadership of doctors and sustained media advocacy—are described; and the paper concludes by looking at prospects for the future, with the forthcoming ban on most forms of tobacco promotion and the challenge of responding to growing demands to protect non-smokers from exposure to other people's tobacco smoke in the workplace and in public places.     

Link-tracing sampling with an initial sequential sample of sites: Estimating the size of a hidden human population

We proposed a modification to the variant of link-tracing sampling suggested by Félix-Medina and Thompson [M.H. Félix-Medina, S.K. Thompson, Combining cluster sampling and link-tracing sampling to estimate the size of hidden populations, Journal of Official Statistics 20 (2004) 19–38] that allows the researcher to have certain control of the final sample size, precision of the estimates or other characteristics of the sample that the researcher is interested in controlling. We achieve this goal by selecting an initial sequential sample of sites instead of an initial simple random sample of sites as those authors suggested. We estimate the population size by means of the maximum likelihood estimators suggested by the above-mentioned authors or by the Bayesian estimators proposed by Félix-Medina and Monjardin [M.H. Félix-Medina, P.E. Monjardin, Combining link-tracing sampling and cluster sampling to estimate the size of hidden populations: A Bayesian-assisted approach, Survey Methodology 32 (2006) 187–195]. Variances are estimated by means of jackknife and bootstrap estimators as well as by the delta estimators proposed in the two above-mentioned papers. Interval estimates of the population size are obtained by means of Wald and bootstrap confidence intervals. The results of an exploratory simulation study indicate good performance of the proposed sampling strategy.     

Computational methods for local regression

Local regression is a nonparametric method in which the regression surface is estimated by fitting parametric functions locally in the space of the predictors using weighted least squares in a moving fashion similar to the way that a time series is smoothed by moving averages. Three computational methods for local regression are presented. First, fast surface fitting and evaluation is achieved by building ak-d tree in the space of the predictors, evaluating the surface at the corners of the tree, and then interpolating elsewhere by blending functions. Second, surfaces are made conditionally parametric in any proper subset of the predictors by a simple alteration of the weighting scheme. Third degree-of-freedom quantities that would be extremely expensive to compute exactly are approximated, not by numerical methods, but through a statistical model that predicts the quantities from the trace of the hat matrix, which can be computed easily.     

Spectral analysis of combustion noise and flame pattern recognition

In many situations, flame patterns in a combustion chamber cannot be observed directly by using an electronic or optical probe. However, an experienced engineer can identify the burning process by listening to the noise that it generates. In this paper, we study acoustic characteristics of turbulent impinging flames by using spectral analysis and statistical pattern recognition. By experimenting with the ignition method, different flame patterns were generated in a laboratory. We find that each flame pattern can be characterized effectively by using the power spectrum of the noise and can be identified by using this information alone.     

A comparison of different procedures for principal component analysis in the presence of outliers

Principal component analysis (PCA) is a popular technique that is useful for dimensionality reduction but it is affected by the presence of outliers. The outlier sensitivity of classical PCA (CPCA) has caused the development of new approaches. Effects of using estimates obtained by expectation–maximization – EM and multiple imputation – MI instead of outliers were examined on the artificial and a real data set. Furthermore, robust PCA based on minimum covariance determinant (MCD), PCA based on estimates obtained by EM instead of outliers and PCA based on estimates obtained by MI instead of outliers were compared with the results of CPCA. In this study, we tried to show the effects of using estimates obtained by MI and EM instead of outliers, depending on the ratio of outliers in data set. Finally, when the ratio of outliers exceeds 20%, we suggest the use of estimates obtained by MI and EM instead of outliers as an alternative approach.     

On the existence of maximum likelihood estimates for weighted logistic regression

The problems of existence and uniqueness of maximum likelihood estimates for logistic regression were completely solved by Silvapulle in 1981 and Albert and Anderson in 1984. In this paper, we extend the well-known results by Silvapulle and by Albert and Anderson to weighted logistic regression. We analytically prove the equivalence between the overlap condition used by Albert and Anderson and that used by Silvapulle. We show that the maximum likelihood estimate of weighted logistic regression does not exist if there is a complete separation or a quasicomplete separation of the data points, and exists and is unique if there is an overlap of data points. Our proofs and results for weighted logistic apply to unweighted logistic regression.     

A new class of modified binomial distributions with applications to certain toxicological experiments ∗

A large class of distributions is proposed to fit the binary data obtained from certain toxicological experiments in which, for example, the outcome of interest is the occurrence of dead or malformed fetuses in a litter. This class of distribution includes the additive model proposed by Altham (1978) as a special case. The fits to three real-life data sets using this new distribution are shown to be much better than those provided by beta-binomial distribution used by Williams (1975) and by the correlated-binomial distribution proposed by Kupper and Haseman (1978).     

地理距离、方言文化与劳动力空间流动

本文基于百度迁徙大数据研究中国劳动力的空间流动，系统考察地理和文化对劳动力流动的影响。通过构造流动机会比率，基于引力模型和普通最小二乘法的研究表明地理距离和方言距离阻碍劳动力流动。在空间距离上，劳动力偏好邻近城市，地理距离每增加1%，劳动力的流动机会比率降低约0.6%。在空间位置上，劳动力倾向于在方言文化相近地域范围流动，方言距离每增加1%，劳动力的流动机会比率下降2%左右。通过构造两地年均降水量差距和小麦种植适宜度差距作为方言距离的工具变量，以两阶段最小二乘法估计缓解内生性问题，估计显示结论稳健。考虑普通话因素后方言距离的抑制影响依然稳健，但目的地的高普通话普及率显著发挥促进劳动力流动的引力作用。最后，本文得出持续推广普通话、加强交通建设和深化中等教育的政策建议。     

On Kendall's Autocorrelations

This brief article extends the theory of sample Kendall's autocorrelations by providing their exact variances at lags higher than one under the null hypothesis of randomness, by introducing and investigating their weighted modifications, and by numerical demonstration of these results and their usefulness.     

Inference in generalized additive mixed modelsby using smoothing splines

Generalized additive mixed models are proposed for overdispersed and correlated data, which arise frequently in studies involving clustered, hierarchical and spatial designs. This class of models allows flexible functional dependence of an outcome variable on covariates by using nonparametric regression, while accounting for correlation between observations by using random effects. We estimate nonparametric functions by using smoothing splines and jointly estimate smoothing parameters and variance components by using marginal quasi-likelihood. Because numerical integration is often required by maximizing the objective functions, double penalized quasi-likelihood is proposed to make approximate inference. Frequentist and Bayesian inferences are compared. A key feature of the method proposed is that it allows us to make systematic inference on all model components within a unified parametric mixed model framework and can be easily implemented by fitting a working generalized linear mixed model by using existing statistical software. A bias correction procedure is also proposed to improve the performance of double penalized quasi-likelihood for sparse data. We illustrate the method with an application to infectious disease data and we evaluate its performance through simulation.     

A theory of statistical models for Monte Carlo integration

Summary. The task of estimating an integral by Monte Carlo methods is formulated as a statistical model using simulated observations as data. The difficulty in this exercise is that we ordinarily have at our disposal all of the information required to compute integrals exactly by calculus or numerical integration, but we choose to ignore some of the information for simplicity or computational feasibility. Our proposal is to use a semiparametric statistical model that makes explicit what information is ignored and what information is retained. The parameter space in this model is a set of measures on the sample space, which is ordinarily an infinite dimensional object. None-the-less, from simulated data the base-line measure can be estimated by maximum likelihood, and the required integrals computed by a simple formula previously derived by Vardi and by Lindsay in a closely related model for biased sampling. The same formula was also suggested by Geyer and by Meng and Wong using entirely different arguments. By contrast with Geyer's retrospective likelihood, a correct estimate of simulation error is available directly from the Fisher information. The principal advantage of the semiparametric model is that variance reduction techniques are associated with submodels in which the maximum likelihood estimator in the submodel may have substantially smaller variance than the traditional estimator. The method is applicable to Markov chain and more general Monte Carlo sampling schemes with multiple samplers.     

Dependence in the 2001 one-number census project

Summary.  The one-number census approach was developed by the Office for National Statistics to adjust the counts from the 2001 census of England and Wales for underenumeration. The method is underpinned by an assumption of independence between the count of the population that was given by the 2001 census and the count that was given by the Census Coverage Survey. Some dependence was, however, detected, and the paper describes the strategy that was used to measure dependence and to adjust the 2001 census population estimates.     

Women in the USSR

This is a selection of statistical data on women in the USSR; it covers the period 1970-1989. Tabular data are provided on the number of women by Union republic; the number of women and men by age group and rural or urban area; women's educational levels, sources of income, and occupations; family size for the whole country and for rural and urban areas; women's marital status by age; marriages and divorces; divorce by women's education, age, and number of children; birth rate by Union republic and by nationality; abortion and childbirth for selected years and by Union republic; maternal deaths by Union republic; infant deaths; and female life expectancy.     

中国时间序列投入产出表的编制:1981—2018

本文提出了以各类统计数据和国民经济核算数据为核心的编制时间序列投入产出表的方法,充分利用国家统计局及其他官方数据源,以国家统计局编制投入产出延长表的方法为基础、以必要的数学方法为辅助。该方法的优点一是编表方法与国家统计局保持内在一致性,数据上能更好地与官方表形成补充和进行衔接;二是充分利用各级部门公布的统计信息,使得所编制的投入产出表能更好地反映编表年度的经济实际。本文利用该方法编制完成我国1981—2018年期间的序列投入产出表,并与已有文献中的几类我国序列投入产出表进行了比较分析。     

国民收入流量矩阵的编制与预测方法研究

本文首先在国家统计局公布的资金流量（实物交易）表的基础上编制了1992-2008年的“部门×交易(S-by-T)”和“部门×部门(S-by-S)”国民收入流量矩阵,设计了一个国民收入流量组合预测模型（The combination forecasting model for national income flow. NCFM）,表述了编表的内容、方法、步骤,配合该模型又设计了国民收入动态均衡模型（The dynamic equilibrium model for national income flow. NDEM）和单方程模型对主要控制总量进行预测,采用状态空间模型对所预测的总量进行了部门和交易分解,用DRAS法编制了2009和2010年的“S-by -T”国民收入流量矩阵的延长表,用“部门收入转移法（SITM）”编制了各年度的“S-by-S”表。最后用Theil’s U、SWAD和STPE三种方法分别对数据质量进行了检验。     

Dynamic generalized linear models with application to environmental epidemiology

Summary. We propose modelling short-term pollutant exposure effects on health by using dynamic generalized linear models. The time series of count data are modelled by a Poisson distribution having mean driven by a latent Markov process; estimation is performed by the extended Kalman filter and smoother. This modelling strategy allows us to take into account possible overdispersion and time-varying effects of the covariates. These ideas are illustrated by reanalysing data on the relationship between daily non-accidental deaths and air pollution in the city of Birmingham, Alabama.     

Empirical Bayes estimation for archaeological stratigraphy

Models and algorithms are presented for the stratigraphic analysis of earth core samples collected at archaeological sites. The aim is to separate the occupation of the site into distinct periods, by dividing the earth core into well-defined blocks of uniform magnetic susceptibility. The models describe the response of detector equipment by using both a spread function and an error process, and they incorporate prior beliefs regarding the nature of the true susceptibility values. The prior parameters are estimated by using pseudolikelihood and the susceptibilities by maximum a posteriori methods via the one-step-late algorithm. These procedures are illustrated with data from synthetic and real core specimens. The new procedures prove to be far superior to other approaches, producing reconstructions which clearly show distinct periods of uniform magnetic susceptibility separated by sharp discontinuities.     

Statistical materials: natural increase of population in the USSR

Data are included on the population of the USSR by sex and Union Republic as of January 1, 1981; birth, death, and natural growth rates for 1979 and 1980; distribution of births, deaths, and marriages by month, 1980; distribution of births by birth order; age distribution of birth rates in urban and rural areas and by Union Republic; death rates from cardiovascular disease and cancer, 1979 and 1980; age at first marriage and marriages by age of bride and groom, 1980; and divorces by duration of marriage and age of spouses, 1980.