Revised regional model life tables at very low levels of mortality

This paper presents and discusses new model life tables at very low mortality, which make use of age-specific death rates from the 1960s, 1970s, and 1980s. These life tables fit recorded death rates in very low mortality populations better than do the existing ones at expectations of life of 77.5 and 80 years. The old tables incorporate too-high mortality at the higher ages and in infancy and they incorporate regional differences that no longer exist. The new tables "close out" the mortality schedules above age 80 more realistically. The convergence of age patterns of mortality at very high life expectancies in populations that used to conform to different families is in itself of demographic interest. Some convergence may perhaps be expected. Sullivan (1973) found that, in Taiwan, the comparison of mortality at ages 1-5 to mortality at 5-35 in the late 1950s showed higher mortality at the younger ages relative to the ensuing 30-year age interval than was found in any of the models, including the South model, which has the highest relative mortality from ages 1-5 among the 4 regional patterns. Then, in the late 1960s, the relation of mortality at 1-5 to mortality at 5-35 in Taiwan fell to a position intermediate between the West and South tables. Sullivan found in data on mortality by cause of death a large reduction in mortality from diarrhea and enteritis, no doubt as a result of environmental sanitation. Mortality from these causes is concentrated among young children, and reduction in deaths from these causes would naturally diminish the excess mortality in this age interval. The East pattern, characterized by very high mortality in infancy (but not from 1-5), may be the result of the prevalence of early weaning or avoidance of breast feeding altogether in the populations characterized by this pattern. As health conditions have improved, evidenced by the overall design of mortality, these special factors are diminished or erased. Model life tables at these very low mortality levels have different uses from most applications of model life tables at higher mortality. The use of model tables to estimate accurate schedules of mortality when the basic data are incomplete or inaccurate is less relevant in this range of mortality levels.     

A reducible four-parameter system of model life tables

Abstract In this paper a four-parameter extension of Brass's relational system of model life tables is suggested that (1) matches a wide range of empirical age patterns of mortality, (2) is easy to apply, especially to partial life tables, and (3) contains demographically meaningful parameters. A test of the model on a set of 62 empirical life tables indicates that four parameters are necessary and sufficient for fitting a wide range of mortality patterns. A further test on an historical series of Swedish life tables reveals a consistent pattern of mortality change. Examination of the parameters for a set of geographicallyrelated life tables suggests a way to define families of life tables. Identification of such temporal and spatial relationships allows the model to be reduced to a form with twoor three-parameters for application to incomplete or inaccurate data.     

On model life tables]

A comparative study and detailed analysis of various standard model life tables are presented. After examining the development of various methods by which demographic factors and weighting techniques are applied, the reasons for the existence of vast discrepancies among the model life tables for various world regions are discussed. It is argued that the 1955 UN model life tables and others developed in Europe and in the United States theoretically apply to Western populations, thus the so-called Chilean, Far East, Southern Asia, and Latin American models, all of which are extensions of Western models, are not totally applicable. Nonetheless, it is concluded that the UN's model population tables 90, 95, and 100 (published in 1955) closely approximate China's 1982 census statistics for life expectancy.     

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.     

The use of model life tables to estimate mortality for the United States in the late nineteenth century

This paper seeks to extend our knowledge about mortality in the late nineteenth century United States by using census mortality data for older children and teenagers to fit model tables. The same method can also be used with partially underregistered death data. The most commonly used model tables, the Coale and Demeny West Model, apparently do not adequately depict the changing shape of mortality over the period 1850--1910. An alternative model life table system is presented, based on the Brass two parameter logit system and available reliable life tables from the period 1850--1910. The two parameter system must be reduced to a one parameter system by means of estimated relationships between the parameters so that the fitting procedure can be used. The resulting model system is, however, heavily dependent on the experience of northern, industrial states, especially Massachusetts.     

Estimating internal migration from incomplete data using model multiregional life tables

A principal feature of current methods of estimating demographic measures from incomplete data is the use of model life tables that approximate the mortality of a region for which reliable mortality data are unavailable. Observed decennial rates of survivorship may be used to identify out of a set of such model life tables one that best matches the observed data. This paper introduces the concept of a modelmultiregional life table and outlines a procedure for selecting an appropriate one using place-of-birth-by-residence data.     

A note on abridged life tables for Ceylon, 1900–1947

Life Tables have been calculated by Kuczynski's method for males and females in Ceylon for 1910–12, 1920–2 and 1945–7. The method is described, and the main results are presented.     

Calculation of life tables from survey data: A technical note

Life table calculations from survey data are frequently based on events for which exact dates are not available. When these dates are coded in monthly form (e.g., century months), estimates should take into account the fact that the first duration interval—the interval which captures events occurring in the first month of exposure—is half the length of all remaining intervals. Although failure to do so has a trivial effect on many demographic calculations, estimates which are based on events which occur with high frequency in the first few months of exposure can be substantially biased. Estimates offecundability for four countries in the World Fertility Survey are used to illustrate this bias.     

Calculating life tables by estimating Chiang’s a from observed rates

A simple, accurate method of life table construction is advanced based upon a new way to estimate Chiang’s _n a _x (the average number of years lived in the x to x + n age interval by those dying in the interval). The estimate for _n a _x leads immediately to an expression for l _x+n (the survivors to age x + n) in terms of l _x and the known mortality rates for the interval x to x+n and the two adjacent intervals. The complete solution for the basic life table is given. The proposed method and five other easily applied methods are then compared against the standard provided by the U.S. life tables for 1969–1971. The results attest to the excellent performance and high degree of accuracy of the proposed method. Finally, extensions of the method to multiple decrement and associated single decrement life tables are briefly described.     

Labor force status life tables for the United States, 1972

As an ordinary life table follows a closed group from birth to the death of its last member, a labor force status life table follows a closed group through life and through the statuses “in the labor force” and “not in the labor force.” Using data from the January 1972 and January 1973 Current Population Surveys, two types of labor force status life tables were calculated for the United States, 1972. One type was a conventional working life table (for males) which started with an ordinary life table and partitioned the life table population into labor force statuses using age-specific proportions in the labor force. The other type was an increment-decrement table, prepared for both males and females, which was calculated so as to be consistent with the rates of labor force accession and separation implied by the data. Increment-decrement labor force status life tables are generally preferable to conventional working life tables. They reflect the implications of a clearly specified set of behavioral rates, provide detailed measures of the flows between labor force statuses, do not introduce seriously biasing approximations into the calculation of summary measures of labor force experience, and can be applied to female data as easily as male data. In practice, incrementdecrement labor force status life tables can be calculated from current and retrospective data generated by a single labor force survey. The increment-decrement labor force status life tables for the United States, 1972 reflected the extent to which the labor force participation of males exceeded that of females, but indicated that, on the average, half a woman’s lifetime between the ages of 16 and 65 was spent in the labor force. There were marked differences in the proportions, by age, of males and females in the labor force, with the male pattern rising to a single, flat peak and the female pattern being bimodal. Nonetheless, the two sexes shared similar age patterns in the proportions changing, or not changing, their labor force status.     

A simple equation for estimating the expectation of life at old ages

Abstract There is much direct and indirect evidence that in a number of populations the ages of older persons tend to be exaggerated, both when reported in censuses and in records of deaths. This results in overestimated expectations of life at old ages. The bias may be corrected by estimating the expectation of life at age a, e(a), from the mortality rate and growth rate at age a and above, M(a+) and r(a+), using the equation developed in this paper: 1/ê(a) = M(a+) exp (β . r(a+). M(a+)(-α)). For a ?, 65, α = 1.4 and β = 0.0951 have been chosen. The value of the equation rests on the following: since ages of older persons tend to be exaggerated, there may be an age a such that most age transfer occurs above that age, and age transfer across the age is small or cancels, so that reasonably accurate values of M(a+) and r(a +) can be obtained, even though ages are badly reported above a. The analysis of artificial data on Gompertzian stable popultions aged over 50 and actual statistics for some selected populations has suggested that the equation provides quite accurate estimates of e(a). The equation also seems useful in closing life tables, since it provides a value of e(a) for the highest age group.     

A flexible two-dimensional mortality model for use in indirect estimation

Mortality estimates for many populations are derived using model life tables, which describe typical age patterns of human mortality. We propose a new system of model life tables as a means of improving the quality and transparency of such estimates. A flexible two-dimensional model was fitted to a collection of life tables from the Human Mortality Database. The model can be used to estimate full life tables given one or two pieces of information: child mortality only, or child and adult mortality. Using life tables from a variety of sources, we have compared the performance of new and old methods. The new model outperforms the Coale-Demeny and UN model life tables. Estimation errors are similar to those produced by the modified Brass logit procedure. The proposed model is better suited to the practical needs of mortality estimation, since both input parameters are continuous yet the second one is optional.     

Voting status life tables for the United States, 1968–1980

Using current and retrospective voting data from the November Current Population Surveys of Presidential election years, this study modifies and applies demographic accounting and increment-decrement life table methods to construct voting status life tables for three recent election periods. The paper shows how to combine a continuously occurring process (mortality) with a process that is active only at discrete times (voting transitions) within a multistate life table. Empirical results pertain to the number of Presidential elections an individual is expected to vote in at ages 0 and 18, the typical life course pattern of transitions between voting and not voting statuses, sex and race differentials, changes across the three election periods, and cohort effects.     

A state-based regression model for estimating substate life expectancy

Life expectancy is an important indicator of the level of mortality in a population. However, the conventional way of calculating life expectancy--constructing a life table--has rigorous data requirements. As a consequence, life expectancy data are not usually available for substate areas. In this article, a regression model for estimating life expectancy is constructed, using state-level data, and is tested against two sets of 1980 life expectancy data: (1) a nationwide sample of metropolitan areas and (2) selected cities, their suburbs, and rural counties in Ohio. An additional test shows the sensitivity of the model's accuracy to errors in one of its input data elements. The results suggest that the model should be given serious consideration for generating life expectancy estimates for substate areas.     

A modified common factor model for modelling mortality jointly for both sexes

Journal of Population Research - There is an increasing attention on the joint modelling of multiple populations. Populations are related in several ways, such as neighbouring countries, females...     

Diet,mortality and life expectancy A cross national analysis

There are numerous reasons why mortality and life expectancy vary between countries. Epidemiological studies seem to indicate that dictary variations may be among them. A sample of 51 countries studied with data from the International Comparisons Project and other sources, shows that after controlling for nutrient intake, consumption of medical goods and services, income distribution, weather, and literacy, countries with more meat and poultry in their diet have lower life expectancies after age five. The results for infant mortality and child death between one and five indicate that a more animal-intensive diet may be actually be beneficial, especially if fish consumption is increased and meat and poultry consumption reduced.I thank Jere Behrman, David Crawford, Anil Deolalikar, the Managing Editor, two anonymous referees, and especially Samuel Preston for valuable comments, and Alan Heston and Robert Summers for being generous with their time and their data. Financial support was provided by a Compton Foundation Fellowship. All errors remain my responsibility.