The estimation of adult mortality in Africa from data on orphanhood

Summary Until recently, very little information has been available about the levels and patterns of adult mortality in tropical Africa, but during the past decade several countries have included questions in censuses and surveys as to whether a person's father and mother are still alive. From the data so obtained, estimates of adult mortality have been prepared. This paper compares the results of three such exercises with alternative estimates of adult mortality derived from other sources. In the case of Chad, the orphanhood data obtained in the demographic sample survey of 1964 yielded estimates of mortality which agreed reasonably closely with those obtained from questions on deaths of household members occurring during the twelve months preceding the survey. The latter data however were themselves subject to substantial errors and had to be corrected using techniques based on stable population theory. For Kenya, the orphanhood questions were included in the 1969 census and the results were compared with the mortality estimates derived from inter-censal survival from 1962 to 1969. Once again, the data obtained from the latter were subject to error but in general appeared to be consistent with the orphanhood estimates. The third comparison was made from Malawi, where alternative mortality figures were available from the Malawi Population Change survey which was a 'dual record' type of operation, conducted in 1971/2. The agreement in this case was remarkably close, once the number of deaths had been corrected for omissions by both systems with allowance for positive correlation. It is concluded that as a simple and inexpensive technique of estimating adult mortality, the orphanhood approach has much to recommend it.     

Fertility and mortality estimation from the Panama Retrospective Demographic Survey, 1976

Summary Data from the Retrospective Demographic Survey of Panama offer a unique opportunity to test a wide range of methods for estimating indirectly basic demographic parameters from inaccurate and incomplete data. Our primary emphasis is to evaluate methods for estimating adult mortality from information on widowhood and orphanhood, though estimates of childhood mortality obtained from information on sibling and child survivorship are assessed as well. The results for most of the estimating procedures are consistent; this finding is encouraging because it lends support to the hypothesis that the techniques can provide good estimates of mortality. Methods which produce results which are inconsistent provide valuable lessons. In particular, methods for providing unconditional estimates of values ofl (x) for adults by combining directly information on childhood mortality and adult mortality are shown to produce estimates which predominantly reflect the level of childhood mortality employed. Furthermore, within-method consistency of estimates appears to be a very poor indicator of reliable performance of the estimating technique or quality of data, since most methods yielded estimates which were internally consistent, though estimates made by different methods could differ considerably. In summary, the analysis indicates a birth rate of around 35 per thousand, a death rate of around 7.5 per thousand, a total fertility ratio of about 4.8, and expectations of life at birth of approximately 59 and 64 years for men and women respectively.     

Orphanhood and adult mortality in the past: a critique of Latin American data and procedures

The author examines the applicability of indirect methods for estimating mortality from information about orphanhood based on methods developed by Brass and Hill using data from Latin America. The author concludes that the data sources available in the region may not be adequate for the application of such techniques.     

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.     

An assessment of methods for estimating adult mortality from two sets of data on maternal orphanhood

Survey and census data about the survival of respondents’ mothers have been used widely for the estimation of adult mortality. Four methods are described that combine two sets of orphanhood data and yield estimates for the intersurvey period. They are applied to enquiries conducted in Peru, Kenya, and Malawi. This provides improved estimates of recent mortality and also clarifies the nature of the errors that affect the basic data. Age misreporting and other errors affect the information about older respondents and orphanhood of children is sometimes underreported. In contrast, data supplied by young adults seem plausible.     

Estimating adult mortality levels from information on widowhood

Summary A range of indirect techniques has been developed for mortality estimation in societies lacking adequate vital registration records. Information on orphanhood has been widely used as an estimator of adult mortality, with generally plausible results. Doubts have remained, however, about potential biases, and the method is less satisfactory for the estimation of male mortality. Information on widowhood, or more strictly the survival of first spouse, has several possible advantages over information on orphanhood. Model first marriage functions and model life tables are used to calculate proportions widowed of first spouse, for both females and males, by marital duration and by age. These proportions widowed are then related to life table survivorship probabilities to provide weighting factors for the conversion of observed proportions widowed into estimates of survivorship probabilities. The application of the method is illustrated with data collected by the 1974 post-enumeration survey of Bangladesh, with apparently encouraging results.     

Differences in life expectancy by education and occupation in Italy, 1980-94: indirect estimates from maternal and paternal orphanhood

In the present study, we use the modified orphanhood method to analyse mortality differences by socio-economic status in Italy. This technique permits the indirect estimation of adult mortality from survey-based information on parents' survival in developed populations and helps to overcome several limitations of conventional studies on mortality differences by social class. We estimate a time series of life tables by education and occupation and analyse the differences in life expectancy by socio-economic status along with their changes between 1980-84, 1985-89, and 1990-94. Whereas mortality differences between the highest social class and the other socio-economic status groups increased among men, they decreased among women. We speculate about the reasons for these sex-specific trends and evaluate the application of indirect estimation techniques to the populations of developed countries.     

Comparison of household-survey estimates with projections of mortality and orphan numbers in sub-Saharan Africa in the era of HIV/AIDS

The United Nations publishes estimates of HIV prevalence, AIDS mortality, and orphan numbers for all countries of the world. It is important to assess the validity of these model-based estimates since they underpin much policy concerned with care and prevention. Household surveys that ask questions about the survival of children's parents (orphanhood) offer an independent source of data with which these estimates can be compared. Survey estimates of maternal and paternal orphans are significantly lower than model estimates for 40 surveys in 36 countries of sub-Saharan Africa (p < 0.001, p = 0.002). This is probably because adult mortality from causes other than AIDS is lower than assumed in the models, although under-reporting of orphanhood in surveys may also play a role. Reducing adult mortality from causes other than AIDS brings the model estimates into close agreement with the surveys. This suggests that the fraction of orphans attributable to AIDS is greater than estimated previously.     

Measurement of adult mortality in less developed countries: a comparative review

"This paper compares the direct and indirect methods used to measure adult mortality in the developing world. No other approach can substitute fully for accurate and complete vital registration, but in many countries it is unrealistic to expect the registration system to cover the majority of the population in the foreseeable future.... The difficulties involved in measuring adult mortality using surveys and other ad hoc inquiries are discussed.... While the choice of methods must depend on each country's situation, direct questions require very large samples and are unreliable in single-round inquiries. On the other hand, although indirect methods provide less detailed and up-to-date information than is ideal, they are adequate for many practical purposes. In particular, the experience of the 1980s suggests that questions about orphanhood perform better than earlier assessments indicated, and recent methodological developments have circumvented some of the limitations of the indirect approach."     

The effects of high HIV prevalence on orphanhood and living arrangements of children in Malawi, Tanzania, and South Africa

Using longitudinal data from three demographic surveillance systems (DSS) and a retrospective cohort study, we estimate levels and trends in the prevalence and incidence of orphanhood in South Africa, Tanzania, and Malawi in the period 1988-2004. The prevalence of maternal, paternal, and double orphans rose in all three populations. In South Africa - where the HIV epidemic started later, has been very severe, and has not yet stabilized - the incidence of orphanhood among children is double that of the other populations. The living arrangements of children vary considerably between the populations, particularly in relation to fathers. Patterns of marriage, migration, and adult mortality influence the living and care arrangements of orphans and non-orphans. DSS data provide new insights into the impact of adult mortality on children, challenging several widely held assumptions. For example, we find no evidence that the prevalence of child-headed households is significant or has increased in the three study areas.     

Mortality in Ghana: Evidence from the cape coast project data

This paper deals with the estimation of mortality for a rural community of about 20,000 persons in the rain-forest area of south-west Ghana. Specifically, infant, child and adult mortality estimates have been obtained by the application of a wide range of direct and indirect methods of measuring mortality from the different statistics collected by a longitudinal mortality and fertility project conducted during 1974–7. It was noted that infant and childhood mortality rates obtained from death registrations were consistent with those rates yielded by pregnancy histories and child survival statistics. However, the adult mortality estimates derived from orphanhood statistics tended to be lower than those suggested by death registrations. The analysis revealed an infant mortality rate of 100 for boys and 84 for girls, equal childhood mortality rates for boys and girls (85–6), a lower expectation of life at birth for men (45.8 years) than for women (52.8), and a much more severe incidence of mortality among men aged over 40 than for women at the corresponding ages.     

Estimating the incidence of widow and widower re-marriages in India from census data

Summary In this paper we develop a method for estimating the incidence of widow and widower re-marriages from the current marital status data given in a census or survey. The method basically consists of reversing the procedure of estimating adult mortality from information on widowhood status. The method is applied to the all-India data from the Census of 1971. The principal result is that about one-third of the ever widowed women and slightly fewer than two-thirds of the ever widowed men were currently remarried in 1971. Similar application of the method to earlier censuses, and to state-level data, may provide answers to some of the riddles in Indian sociology.     

Mortality in Ghana: Evidence from the cape coast project data

Abstract This paper deals with the estimation of mortality for a rural community of about 20,000 persons in the rain-forest area of south-west Ghana. Specifically, infant, child and adult mortality estimates have been obtained by the application of a wide range of direct and indirect methods of measuring mortality from the different statistics collected by a longitudinal mortality and fertility project conducted during 1974-7. It was noted that infant and childhood mortality rates obtained from death registrations were consistent with those rates yielded by pregnancy histories and child survival statistics. However, the adult mortality estimates derived from orphanhood statistics tended to be lower than those suggested by death registrations. The analysis revealed an infant mortality rate of 100 for boys and 84 for girls, equal childhood mortality rates for boys and girls (85-6), a lower expectation of life at birth for men (45.8 years) than for women (52.8), and a much more severe incidence of mortality among men aged over 40 than for women at the corresponding ages.     

The consequences of HIV/AIDS in Eastern Africa on mothers,children, and orphans

Orphanhood is a sad and unique problem of the HIV pandemic, compared with other epidemics, for generally both parents will be infected and will tend to die during young adulthood, leaving behind young children. The rising morbidity and mortality of HIV-infected mothers and fathers threaten to decrease the care and resources spent on children and to increase the prevalence of orphanhood. However, the extent and impact of orphanhood due to HIV/AIDS are not known. This paper presents two aspects of HIV infection and its impact on women and children in sub-Saharan Africa: the results of two analyses of the HIV-attributable mortality of mothers and the orphanhood of their young children.     

Adult mortality in sub-Saharan Africa: Evidence from demographic and health surveys

This article reports levels, trends, and age patterns of adult mortality in 23 sub-Saharan Africa countries, based on the sibling histories and orphanhood data collected by the countries' Demographic and Health Surveys. Adult mortality has risen sharply since HIV became prevalent, but the size and speed of the mortality increase varies greatly among countries. Excess mortality is concentrated among women aged 25-39 and among men aged 30-44. These data suggest that the increase in the number of men who die each year has exceeded somewhat the increase for women. It is time for a systematic attempt to reconcile the demographic and epidemiological evidence concerning AIDS in Africa.     

Assessing the Potential Impact of the HIV-1 Epidemic on Orphanhood and the Demographic Structure of Populations in sub-Saharan Africa

Much of the debate on the demographic consequences of the HIV epidemic in sub-Saharan Africa has so far centred around the plausibility of population declines in areas where unprecendently high rates of population growth have recently been in evidence. In this article, the authors use a mathematical model, which combines epidemiological and demographic processes, to illustrate how, under a broad range of impacts on population growth, major changes in demographic features, such as the extent of orphanhood within populations, are likely to occur. At the same time, HIV epidemics are liable to cause significant shifts in the age and sex composition of affected populations, which may have important implications for the ways in which they are best able to cope with the increases in orphanhood, as well as those in infant, early childhood and adult mortality.     

Orphanhood and Human Capital Destruction: Is There Persistence into Adulthood?

This article presents unique evidence that orphanhood matters in the long run for health and education outcomes in a region of northwestern Tanzania. We study a sample of 718 non-orphaned children surveyed in 1991–1994 who were traced and reinterviewed as adults in 2004. A large proportion, 19%, lost one or more parents before age 15 in this period, allowing us to assess permanent health and education impacts of orphanhood. In the analysis, we control for a wide range of child and adult characteristics before orphanhood, as well as community fixed effects. We find that maternal orphanhood has a permanent adverse impact of 2 cm of final height attainment and one year of educational attainment. Expressing welfare in terms of consumption expenditure, the result is a gap of 8.5% compared with similar children whose mothers survived until at least their 15th birthday.     

Death by survey: Estimating adult mortality without selection bias from sibling survival data

The widely used methods for estimating adult mortality rates from sample survey responses about the survival of siblings, parents, spouses, and others depend crucially on an assumption that, as we demonstrate, does not hold in real data. We show that when this assumption is violated so that the mortality rate varies with sibship size, mortality estimates can be massively biased. By using insights from work on the statistical analysis of selection bias, survey weighting, and extrapolation problems, we propose a new and relatively simple method of recovering the mortality rate with both greatly reduced potential for bias and increased clarity about the source of necessary assumptions.     

Further developments in indirect mortality estimation

Summary A variety of indirect estimators of mortality; survival of children by marriage duration of mother, survival of first spouse by marriage duration and by age, maternal orphanhood, and survival of siblings, are investigated by the use of a wide range of model fertility and mortality situations. Survival probabilities are then related by regression analysis to the proportions with a particular characteristic, to yield an equation which can then be used to estimate the survival probability in a population. Maternal orphanhood and survival of first spouse by age have already shown themselves to be useful, and the new developments are only simplifications of the existing methodology. Survival of first spouse by duration of marriage, and survival of siblings are, however, new methods which have yet to be justified by field experience. In conclusion, the features common to all indirect mortality estimation procedures are outlined, and the direction future developments may take in response to gradually improving data quality is suggested.     

The completeness of enumeration in the 1973 census of the population of Colombia

The effort is made to determine the true size and distribution by age and sex of the population of the Republic of Colombia in October 1973. After initially arriving at estimates of the levels of fertility and mortality during the intercensal period and then correcting the 1964 census population for age misreporting and selective undernumeration of males, a hypothetical populaiton corresponding to October 1973 is constructed. Comparing the constructed population with the population observed in the census yelds an estimate of completeness of enumeration in 1973 that is relative to the enumeration of females in 1964. This estimate is obtained under the assumption that net international migration during the period was of negligible importance. As there is reason to believe that this is not a valid assumption and upon examining the limited amount of evidence available, speculaitons are made concerning the amount of net out-migration to have occurred during the 1964-1973 period and the size of the coresponding modificaiton in the estimate of completeness of enumeration. After adjusting for underenumeration of males in 1964 and neglecting the impact of international migration, a theoretical 1973 census population of 23,201,000 was estimated. Apart from the total number of people enumerated, the information that was analyzed from the advance sample appears to be of good quality, at least in relation to prior censuses. The estimates of fertility and mortality reveal an important decline in Colombian fertility. By coming up with separate estimates of infant and childhood and adult mortality, it has been possible to shed new light on the shape and the level of mortality in Colombia. The new Brass method for estimating adult mortality provides reliable results even when mortality has been declining, and there are recognizable distortions in the distribution of the population by age.