Estimation of local demographic variation in a flexible framework for population projections

A cohort component projection of local populations based on sex and single year of age offers great value for planning local services, but demands data beyond the detail available. Local fertility, mortality and migration schedules by age and sex must be estimated sensitively to local variation if the results are to be of greater value than simpler methods of projection. Two approaches are compared, using data for the recent past: (a) direct estimation of local area age-specific schedules of fertility, mortality and migration based on data available to the national statistical agency; (b) graduation of national schedules using only local area population estimates by age, total numbers of births, and total numbers of deaths; age-specific migration is indirectly estimated from successive population estimates. These two approaches are compared with a projection using the same rates for each area. The three projections have been implemented for electoral wards in the Fife local government area of Scotland, using the flexible framework provided by POPGROUP software. Persuasive local population projections based on standard data for standard areas are feasible without the regular publication of migration flows.     

Estimating Mortality Differences in Developed Countries From Survey Information on Maternal and Paternal Orphanhood

In general, the use of indirect methods is limited to developing countries. Developed countries are usually assumed to have no need to apply such methods because detailed demographic data exist. However, the potentialities of demographic analysis with direct methods are limited to the characteristics of available macro data on births, deaths, and migration. For instance, in many Western countries, official population statistics do not permit the estimation of mortality by socioeconomic status (SES) or migration background, or for estimating the relationship between parity and mortality. In order to overcome these shortcomings, I modify and extend the so-called orphanhood method for indirect estimation of adult mortality from survey information on maternal and paternal survival to allow its application to populations of developed countries. The method is demonstrated and tested with data from two independent Italian cross-sectional surveys by estimating overall and SES-specific life expectancy. The empirical applications reveal that the proposed method can be used successfully for estimating levels and trends of mortality differences in developed countries and thus offers new prospects for the analysis of mortality.     

Assessing structural change in U.S. migration patterns: a log-rate modeling approach

"A set of log-rate models is proposed to transform Rogers and Wilson's accounting-based migration models into statistics-oriented migration models. This study demonstrates not only how log-rate models can be used to replicate results generated from Rogers-Wilson's cohort and multi-region mobility models, but also how log-rate models can be used to make statistical inferences and to derive more parsimonious models. Estimation issues and model fit are discussed, and case studies with U.S. mobility and interregional migration data are provided. The flexibility of log-rate models is emphasized, and possible uses for such models, such as the testing of various hypotheses and migration projection, are explored. Potential applications and limitations of log-rate models are also discussed." (EXCERPT)     

Estimation of period-specific gross migration flows from limited data: Bi-proportional adjustment approach

Two models, hierarchical in terms of input data requirements, are proposed to estimate place-to-place gross migration flows during a specified time period. In the first, the input data required are lifetime migration flows and the marginal totals of period migration, usually available from national censuses. The estimational algorithm is a ‘bi-proportional adjustment’ technique (and its variant) that assumes structural similarity between lifetime and period migration flows. The second model is designed to account for possible structural deviations in recent migratory patterns. Calibration of the procedure to replicate Indian and Korean data confirms high validity of estimation.     

1936年安徽保甲户口编查数据的考察

考察人口统计数据是历史人口研究的第一步。文章溯本清源,梳理了1936年安徽保甲户口编查数据的来源,考察了其质量,并利用历史人口学的方法对1936年安徽的人口数量进行了大概规模的复原。     

Infant mortality in the Marshall Islands

Levy and Booth present previously unpublished infant mortality rates for the Marshall Islands. They use an indirect method to estimate infant mortality from the 1973 and 1980 censuses, then apply indirect and direct methods of estimation to data from the Marshall Islands Women's Health Survey of 1985. Comparing the results with estimates of infant mortality obtained from vital registration data enables them to estimate the extent of underregistration of infant deaths. The authors conclude that 1973 census appears to be the most valid information source. Direct estimates from the Women's Health Survey data suggest that infant mortality has increased since 1970-1974, whereas the indirect estimates indicate a decreasing trend in infant mortality rates, converging with the direct estimates in more recent years. In view of increased efforts to improve maternal and child health in the mid-1970s, the decreasing trend is plausible. It is impossible to estimate accurately infant mortality in the Marshall Islands during 1980-1984 from the available data. Estimates based on registration data for 1975-1979 are at least 40% too low. The authors speculate that the estimate of 33 deaths per 1000 live births obtained from registration data for 1984 is 40-50% too low. In round figures, a value of 60 deaths per 1000 may be taken as the final estimate for 1980-1984.     

Effects of targets and aggregation on the propagation of error in mortality forecasts

Official forecasts of mortality depend on assumptions about target values for the future rates of decline in mortality rates. Smooth functions connect the jump‐off (base‐year) mortality to the level implied by the targets. Three alternative sets of targets are assumed, leading to high, middle, and low forecasts. We show that this process can be closely modeled using simple linear statistical models. These explicit models allow us to analyze the error structure of the forecasts. We show that the current assumption of perfect correlation between errors in different ages, at different forecast years, and for different causes of death, is erroneous. An alternative correlation structure is suggested, and we show how its parameters can be estimated from the past data.

The effect of the level of aggregation on the accuracy of mortality forecasts is considered. It is not clear whether or not age‐ and cause‐specific analyses have been more accurate in the past than analyses based on age‐specific mortality alone would have been. The major contribution of forecasting mortality by cause appears to have been in allowing for easier incorporation of expert opinion rather than in making the. data analysis more accurate or the statistical models less biased.     

A simple method to estimate insect mortality from field census data: A modification of the Kiritani-Nakasuji-Manly method

Various methods have been proposed to estimate demographic parameters such as mortality from field census data. Simple methods proposed earlier are applicable only for limited situations. For example, the Kiritani-Nakasuji-Manly method is applicable only if individuals are observable until their death. Improved methods proposed later are not subject to such limitations, but are not so widely used in the field of applied entomology, probably because of the complexity of the calculations involved. In this paper, I propose an intermediate method that requires only a pocket calculator, considering the practical convenience for field scientists. This method, which is a modification of the Kiritani-Nakasuji-Manly method, gives an estimate of the number of individuals entering a stage from the frequency of two stages when the stage duration is known.     

Mixed estimation of old‐age mortality

The estimation of the mortality of the “oldest old”; is subject to considerable random error, but important prior information exists that can be used to make the estimates more robust. Mixed estimation is a method of incorporating auxiliary information into the statistical estimation of linear models. We extend the method to cover general maximum likelihood estimation, and show that the mixed estimator can be represented approximately as a weighted average of the purely data based estimator and the auxiliary estimator. The methods can be applied to the analysis of the old‐age mortality via logistic and Poisson regression. A major advantage of the mixed estimator is the simplicity with which it can incorporate partial prior information. Moreover, no special software is needed in the fitting. We show how the targeting methods of Coale and Kisker can be represented as mixed estimation in a natural way that is more flexible than the original proposal. We also derive empirical estimates of the target information based on pooled data from several countries with high quality data. We consider the mortality of Finland at ages 80 +, study the reliability of the evidence of mortality crossover, and derive estimates of life expectancy at age 100.     

A simplified robust estimate of the birth rate

It is shown that other estimates of the birthrate can be derived from Coale's robust birthrate estimate. Coale's estimate is nearly equal to the birthrate obtainable from reverse survival or reverse projection of the proportion of a population under age 15 (both sexes), or C(15), using a life table corresponding to l5. As a sequel to this, a birth rate estimate was obtained that does not require reference to stable population models and results in computational economy and ease. Taking advantage of the strong linear relation between l5 and 15L0, a simple robust estimate was derived of the birthrate that does not depend upon model stable populations or model life tables. After presenting these methods, their use is illustrated with data from several Asian and African countries. Coale (1981) suggested using the observed C(15) for both sexes and l5 to locate an appropriate stable population from a family of stable models to represent the observed population and to use its birthrate as an estimate of the population under study. The estimate of l5 can be obtained by any of the indirect methods like the Brass method. Coale observed that such methods yield birthrates that are not much affected even when the populations are not stable. He also suggested an adjustment for the stable birthrate for nonstability. To obtain the birthrate, one needs the denominator, namely, the number of persons that lived. This is obtained by using the rate of increase, r, which differs for a stable and a nonstable or observed population. Various methods can be used to obtain the time reference of the mortality estimate, l5, by providing years prior to the survey or census to which the l5 estimate is applicable.     

BRASS' RELATIONAL MODEL: A STATISTICAL ANALYSIS

Brass' relational model is based on a linear relationship between the logits of the cumulative probability of dying before age x in a standard mortality distribution and those observed in any population. In this study the appropriate way to estimate the linear parameters associated with Brass' model is clarified. Five methods are presented to estimate the coefficients associated with Brass' relational model. Each method is applied to simulated data to examine the efficiencies of each model in mortality estimation.     

Do Not Go Gentle Into That Good Night: The Effect of Retirement on Subsequent Mortality of U.S. Supreme Court Justices, 1801–2006

Mortality hazard and length of time until death are widely used as health outcome measures and are themselves of fundamental demographic interest. Considerable research has asked whether labor force retirement reduces subsequent health and its mortality measures. Previous studies have reported positive, negative, and null effects of retirement on subsequent longevity and mortality hazard, but inconsistent findings are difficult to resolve because (1) nearly all data confound retirement with unemployment of older workers, and often, (2) endogeneity bias is rarely addressed analytically. To avoid these problems, albeit at loss of generalizability to the entire labor force, I examine data from an exceptional subgroup that is of interest in its own right: U.S. Supreme Court justices of 1801–2006. Using discrete-time event history methods, I estimate retirement effects on mortality hazard and years-left-alive. Some substantive and methodological considerations suggest models that specify endogenous effects estimated by instrumental variables (IV) probit, IV Tobit, and IV regression methods. Other considerations suggest estimation by endogenous switching (ES) probit and ES regression. Estimates by all these methods are consistent with the hypothesis that, on average, retirement decreases health, as indicated by elevated mortality hazard and diminished years-left-alive. These findings may apply to other occupational groups characterized by high levels of work autonomy, job satisfaction, and financial security.     

Family migration and changes in women's earnings: A decomposition analysis

Married women who migrate with their families experience relative earnings losses after migration. In this study, we use data from the 1987 Wave of the Panel Study of Income Dynamics to explicitly examine the relative importance of three sources of those losses: labor force participation, hours of labor supplied, and wages. We estimate earnings models with Heckman's sample selection method for each of four years following migration. The results and subsequent coefficient decomposition methods show that labor force exit and a reduction of labor supplied contribute the largest share to the earnings penalty attached to migration for married women. The participation effect, although reduced in size, is significant for three years following migration. The wages of employed married women who migrate appear to be unaffected in any year following migration.     

Comparing two survey methods for estimating maternal and perinatal mortality in rural Cambodia

PURPOSE: We need solid estimates of maternal mortality rates (MMR) to monitor the impact of maternal care programs. Cambodian health authorities and WHO report the MMR in Cambodia at 450 per 100,000 live births. The figure is drawn from surveys where information is obtained by interviewing respondents about the survival of all their adult sisters (sisterhood method). The estimate is statistically imprecise, 95% confidence intervals ranging from 260 to 620/100,000. The MMR estimate is also uncertain due to under-reporting; where 80-90% of women deliver at home maternal fatalities may go undetected especially where mortality is highest, in remote rural areas. The aim of this study was to attain more reliable MMR estimates by using survey methods other than the sisterhood method prior to an intervention targeting obstetric rural emergencies. PROCEDURES: The study was carried out in rural Northwestern Cambodia where access to health services is poor and poverty, endemic diseases, and land mines are endemic. Two survey methods were applied in two separate sectors: a community-based survey gathering data from public sources and a household survey gathering data direct from primary sources. FINDINGS: There was no statistically significant difference between the two survey results for maternal deaths, both types of survey reported mortality rates around the public figure. The household survey reported a significantly higher perinatal mortality rate as compared to the community-based survey, 8.6% versus 5.0%. Also the household survey gave qualitative data important for a better understanding of the many problems faced by mothers giving birth in the remote villages. There are detection failures in both surveys; the failure rate may be as high as 30-40%. PRINCIPLE CONCLUSION: Both survey methods are inaccurate, therefore inappropriate for evaluation of short-term changes of mortality rates. Surveys based on primary informants yield qualitative information about mothers' hardships important for the design of future maternal care interventions.     

The use of hypothetical cohorts in estimating demographic parameters under conditions of changing fertility and mortality

The indirect methods of demographic estimation available to date are often inadequate to estimate levels in the presence of trends. The use of measures relative to hypothetical cohorts to minimize the effectsoftrends and estimate period levels is described. Procedures allowing the estimation of intersurvey levels of fertility, child mortality and adult mortality are illustrated using data from Thailand and Peru.     

Lee-Carter估计模式推算中国农村老年人口死亡率的研究

死亡率的估算与人口老龄化密切相关,中国60岁及以上老年人口主要集中在农村地区,本文运用Lee-Carter模型对农村分性别单岁组的死亡率数据进行建模,预测出农村人口死亡率与期望寿命的发展趋势。     

Malthus in state space: Macro economic-demographic relations in English history, 1540 to 1870

. The history of preindustrial Europe provides an opportunity to examine the causes and consequences of population change at a macro level. However, serious statistical problems arise from the endogeneity of all observed variables in a Malthusian system (fertility, mortality, population size, and real wages), and from unobserved influences such as shifts in the demand for labor and variations in health. These problems have undermined both informal inference from the data and more complex econometric investigations. This paper takes a new statistical approach, finding the maximum likelihood estimate of a state space representation of the Malthusian system by repeated application of Kalman filter methods, using annual data from England, 1540 to 1870. The new estimates confirm some findings of the earlier literature and contradict others. Some variables are estimated for the first time. Implications are discussed for the interpretation of English economic-demographic history. Received: 3 January 2000/Accepted: 22 January 2001     

Migration bias in indirect estimates of regional childhood mortality levels

Demographers often use Brass‐style indirect methods to obtain childhood mortality estimates for regions within developing countries. Regional populations are not closed to migration, however, and mortality reports of women resident in a certain region on the survey date may contain information on events and exposure that occurred elsewhere as the mother migrated. Including this “imported”; mortality information may cause significant bias in regional estimates. In this paper the authors: (1) investigate the possible magnitude of migration bias using a multiregional simulation model, (2) propose a modification to standard methods which should reduce bias in many circumstances, and (3) apply the modified technique to data from Brazil's 1980 Census. We find that migration bias can indeed be significant, and that in the specific case of São Paulo state, imported mortality information may result in overestimates of local mortality levels of 10–15% when using Brass‐style methods.     

Exploring Child Mortality Risks Associated with Diverse Patterns of Maternal Migration in Haiti

Internal migration is a salient dimension of adulthood in Haiti, particularly among women. Despite the high prevalence of migration in Haiti, it remains unknown whether Haitian women’s diverse patterns of migration influence their children’s health and survival. In this paper, we introduce the concept of lateral (i.e., rural-to-rural, urban-to-urban) versus nonlateral (i.e., rural-to-urban, urban-to-rural) migration to describe how some patterns of mothers’ internal migration may be associated with particularly high mortality among children. We use the 2006 Haitian Demographic and Health Survey to estimate a series of discrete-time hazard models among 7,409 rural children and 3,864 urban children. We find that compared with their peers with nonmigrant mothers, children born to lateral migrants generally experience lower mortality, whereas those born to nonlateral migrants generally experience higher mortality. Although there are important distinctions across Haiti’s rural and urban contexts, these associations remain net of socioeconomic factors, suggesting they are not entirely attributable to migrant selection. Considering the timing of maternal migration uncovers even more variation in the child health implications of maternal migration; however, the results counter the standard disruption and adaptation perspective. Although future work is needed to identify the processes underlying the differential risk of child mortality across lateral versus nonlateral migrants, the study demonstrates that looking beyond rural-to-urban migration and considering the timing of maternal migration can provide a fuller, more complex understanding of migration’s association with child health.     

Parental survival data: Some results of the application of Ledermann's model life tables

Summary Ledermann's one- and two-parameter model life tables are used in order to summarize and compare adult mortality estimates derived from parental survival data, and also to link parental survival with child survival data. The Ledermann models provide an alternative to the logit model used by Brass and Hill. Examination of life tables derived from actual child and adult mortality estimates reveals that although the two types of models yield similar overall levels of mortality, they show marked differences in the estimated patterns by sex and age. It has not been possible to disentangle completely how much of this divergence is due to the models themselves and how much to inadequacies in the data available. Finally, we question whether it is always wise to establish a full life table from child and adult mortality estimates when these are based on data which refer to different periods of exposure to the risk of dying, without allowance for possible distortions resulting from mortality change.