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.     

Measuring maternal mortality through the census: rapier or bludgeon?

There is increased demand for maternal mortality estimates as a result of the choice of the Maternal Mortality Ratio as the key indicator for Millennium Development Goal 5. Given this strong demand, the United Nations Principles and Recommendations for Population Censuses suggest the inclusion of questions on recent household deaths, plus questions to identify pregnancy-related deaths in countries lacking empirical, national estimates. This paper evaluates the results of census-based measurement of pregnancy-related mortality using three different types of consistency checks applied in selected countries. Results from these evaluations are mixed. Overall, the census approach seems to produce robust estimates of the number of births. However, the consistency and plausibility of results relating to mortality vary substantially by country and by indicator. It is not clear whether the census-based methodology performs better or worse than the frequently used sibling histories. The results presented here clearly demonstrate the need for careful data evaluation and interpretation.     

Childhood Mortality Estimates Using the Preceding Birth Technique: Some Applications and Extensions

The Preceding Birth Technique has proved to be a simple and effective way of estimating mortality during the first two years of life when the question on the survival of the preceding child is asked at the time of a subsequent delivery. This article shows first that earlier worries about significant biases in the estimates are unfounded. Amongst the possible sources of bias considered are: the link between birth-interval length and child survival; the effects of birth intervals differing from 30 months; and the contribution of other systematic biases, such as the omission of all reports on the survival of a woman's last child. Results from a trial in the maternity clinics in Bamako, Mali are presented to illustrate both practical aspects of the method and selection effects by age and parity. A strong association between the survival chances of the succession of children born to one mother emerges. The second part of the article describes how the method can be applied more widely by asking the key questions at times other than a subsequent delivery. Adjustment factors are developed to correct for the biases introduced when the sample includes only mothers whose last-born children are alive at interview.Finally, some examples are given of recent use of the question on the survival of the preceding child in household surveys.     

Mortality in China 1964-2000

This paper uses data from censuses and surveys to re-estimate mortality levels and trends in China from the 1960s to 2000. We use the General Growth Balance method to evaluate the completeness of death reporting above the youngest ages in three censuses of the People's Republic of China from 1982 to 2000, concluding that reporting quality is quite high, and revisit the completeness of death recording in the 1973-75 Cancer Epidemiology Survey. Estimates of child mortality from a variety of direct and indirect sources are reviewed, and best estimates arrived at. Our estimates show a spectacular improvement in life expectancy in China: from about 60 years in the period 1964-82 to nearly 70 years in the period 1990-2000, with a further improvement to over 71 years by 2000. We discuss why survival rates continue improving in China despite reduced government involvement in and increasing privatization of health services, with little insurance coverage.     

An alternative sampling strategy for obtaining child health data in a reproductive health survey

Retrospective demographic surveys typically collect substantial information about child health. This information is often collected for all children born during a specified period. For women with several young children, the interview can become quite long. To shorten the interview, some surveys have asked child health questions only for the last child born. However, data on the last birth may be biased because last children have a younger age distribution and have longer subsequent birth intervals than does the average child. In this paper, we propose an alternative approach to collecting child health data - that child health questions be asked only for a child chosen randomly from among the respondent's children younger than age five. This alternative has the advantage of keeping the interview shorter but does not lead to biased information.Abbreviations DHS Demographic and Health Surveys     

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.     

Some aspects of the relationship between the levels of infant mortality and fertility in the ESCAP region

The death of a child within the first year of life is a crucial factor in fertility decisions in a developing country. The infant mortality rate gives a close, inverse indication of the socioeconomic conditions of a country. This paper presents studies by Brass, Rutherford, Chowdhury, Khan and Chen, Agrawal, Iskander and Jones, in summary/abstract form. It concludes that the probabilities of survival are poorer for births of older women and/or higher parities. Early child deaths may increase the total period of exposure to the risk of conception. A lower infant and child mortality norm calls for fewer births to meet the needs for survivors. Child replacement motivational response seems to be strongest with the birth immediately following a death event. Agrawal analyzed the interval between successive births of 1107 women of Patna, Pakistan, according to the age of mother and sex and fate of the previous child. He observed that if a child died shortly after its birth, often a new pregnancy began within a short interval. The interval between 2 consecutive live births when the previous child was male and alive was greater than when the previous child was female and alive. The interval between 2 births was reduced if the child died in infancy and specially if this was a male child.     

The Level and Age Pattern of Mortality in Bandafassi (Eastern Senegal): Results From a Small-Scale and Intensive Multi-Round Survey

The data collected in the Bandafassi demographic study in Eastern Senegal, a small-scale intensive and experimental follow-up survey of a population of about 7,000 in 1983, were analysed to derive an estimated life table. The use of multi-round surveys, combined with anthropological methods to estimate ages and collect genealogies, has resulted in unusually reliable data. Taking into account the uncertainty of the estimates due to the small size of the population, mortality was high, with life-expectancy at birth close to 31 years; a pattern of infant and child mortality close to that observed in other rural areas of Senegal, with a very high level or mortality between ages six months and three years; a seasonal pattern in child mortality with two high-risk periods, the rainy season and the end of the dry season; an adult mortality pattern similar to that described in model life tables for developed countries; no significant difference by sex or ethnic group. The Bandafassi population study and a few similar studies suggest that one possible way to improve demographic estimates in countries where vital registration systems are defective would be to set up a sample of population laboratories where intensive methods of data collection would continue for extended periods.     

Estimation of demographic measures for India, 1881-1961, based on census age distributions

Abstract India is one of the very few developing countries which have a relatively long history of population censuses. The first census was taken in 1872, the second in 1881 and since then there has been a census every ten years, the latest in 1971. Yet the registration of births and deaths in India, even at the present time, is too inadequate to be of much help in estimating fertility and mortality conditions in the country. From time to time Indian census actuaries have indirectly constructed life tables by comparing one census age distribution with the preceding one. Official life tables are available for all the decades from 1872-1881 to 1951-1961, except for 1911-1921 and 1931-1941. Kingsley Davis(1) filled in the gap by constructing life tables for the latter two decades. He also estimated the birth and death rates ofIndia for the decades from 1881-1891 to 1931-1941. Estimates of these rates for the following two decades, 1941-1951 and 1951-1961, were made by Indian census actuaries. The birth rates of Davis and the Indian actuaries were obtained basically by the reverse survival method from the age distribution and the computed life table of the population. Coale and Hoover(2), however, estimated the birth and death rates and the life table of the Indian population in 1951 by applying stable population theory. The most recent estimates of the birth rate and death rate for 1963-1964 are based on the results of the National Sample Survey. All these estimates are presented in summary form in Table 1.     

A comparison of different survey techniques for obtaining vital data in A developing country

This article presents estimates of the sources and the extent of observation errors in different questionnaires and methods used to collect birth and death data in the 1961-63 multi-purpose sample survey of Morocco.The questionnaires used in the analysis of the three survey rounds were a list of household members (Rounds1 and 2) and a roll-call (Round3); retrospective death (Rounds1, 2, and 3) and birth (Round 3) queries; a date-of-birth tabulation (Round 2); and a household check-sheet to explain differences between Rounds 1 and 2. All available questionnaires for a given household were brought together and collated to provide several sources of information on births and deaths and a basis for assessing errors.From this analysis, the survey attempted to define the nature and to estimate the frequency of the errors which would have occurred if more restricted types of survey design had been used. Results, based on the period between Rounds 1 and 2, led to three major conclusions.First, if vital data had been collected with a single-round retrospective procedure, gross error (over enumeration plus underenumeration) would have been 17 percent for births and 36 percent for deaths. There is a net error of overenumeration of 3 percent for births (1.4 per1,000population) and 9 percent for deaths (2.3 per1,000population).Second, if two rounds were available to permit a combination of household composition follow-up and a retrospective mortality questionnaire, overenumeration would be almost entirely eliminated and underenumeration would be noticeably reduced. Third, most of the remaining errors of underestimation may be attributed to (1) an estimated number of infants born and deceased between two rounds and missed by all questionnaires, (2) matching failures caused by the absence of adults at Round 1, and (3) matching errors.     

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.     

Estimation of vital rates for Ghana

Abstract A complete and efficient registration system, of the type which would provide good data on births and deaths, does not exist in Ghana. However, registration of vital events is supposed to be compulsory in 39 towns in the country but the data collected in these areas are too inadequate and defective to provide a sound basis for the analysis of the dynamics of population growth. The results of the censuses conducted by the colonial governments are so defective and unreliable that they do not allow scientific research in the field of population analysis. Before 1960, therefore, when the national census and the post-enumeration survey (based on a 5% sample of the population) were carried out, estimates of fertility and mortality levels were little more than guesses. In this study an attempt has been made to utilize the information on the age-sex composition provided by the 1960 census and post-enumeration survey data on births and deaths to determine, as far as possible, the levels of fertility and mortality and the rates of population growth in Ghana. The fertility estimates-i.e. a crude birth rate of 50, total fertility rate of 6.9 and a gross reproduction rate of 3.4-show that Ghana's fertility is one of the highest in the world. An expectation of life at birth of 40 years, an infant mortality of 160 and a crude death rate of 23 appear to be the most plausible estimates. These estimates yield a rate of natural increase of 2.7% and a growth rate of 3.0% per annum.     

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.     

How Far Has Fertility in China Really Declined?

According to births in the last year as reported in China's 2000 census, the total fertility rate (TFR) in the year 2000 in China was 1.22 children per woman. This estimate is widely considered to be too low, primarily because some women who had out‐of‐quota births according to China's one‐child family policy did not report those births to the census enumerator. Analysis of fertility trends derived by applying the own‐children method of fertility estimation to China's 1990 and 2000 censuses indicates that the true level of the TFR in 2000 was probably between 1.5 and 1.6 children per woman. A decomposition analysis of change in the TFR between 1990 and 2000, based on our best estimate of 1.59 for the TFR in 2000, indicates that about two‐fifths of the decline in the conventional TFR between 1990 and 2000 is accounted for by later marriage and less marriage, and three‐fifths by declining fertility within marriage. The analysis also applies the birth history reconstruction method of fertility estimation to the two censuses, yielding an alternative set of fertility estimates that are compared with the set derived by the own‐children method. The analysis also includes estimates of trends in fertility by urban/rural residence, education, ethnicity, and migration status. Over time, fertility has declined sharply within all categories of these characteristics, indicating that the one‐child policy has had large across‐the‐board effects.     

Reconstruction of Birth Histories from Census and Household Survey Data

In this paper a new procedure for reconstructing birth histories from census or household survey data is developed. Given the number of children ever born, the number of deceased children, and the ‘own children’ birth history of each woman, it is possible to ‘fill in’ probabilistically the missing births of her deceased children and of children not present in the household. Thus, the procedure generates complete birth histories from which such measures as age-specific fertility rates, parity progression ratios, and birth interval measures may be estimated. For purposes of illustration and validation, the method is applied to the household survey data of the 1974 Korean National Fertility Survey, both to the entire sample of households, and to households with women from whom individual birth histories were collected. Age-specific fertility rates and parity progression measures estimated from the reconstructed birth histories are compared with those estimated by applying the ‘own children’ method, for the period 1960–74.     

Child survivorship estimation: methods and data analysis

"The past 20 years have seen extensive elaboration, refinement, and application of the original Brass method for estimating infant and child mortality from child survivorship data. This experience has confirmed the overall usefulness of the methods beyond question, but it has also shown that...estimates must be analyzed in relation to other relevant information before useful conclusions about the level and trend of mortality can be drawn.... This article aims to illustrate the importance of data analysis through a series of examples, including data for the Eastern Malaysian state of Sarawak, Mexico, Thailand, and Indonesia. Specific maneuvers include plotting completed parity distributions and 'time-plotting' mean numbers of children ever born from successive censuses. A substantive conclusion of general interest is that data for older women are not so widely defective as generally supposed."     

Advances in the P/F ratio method for the analysis of birth histories

Abstract One of the most frequently used indirect techniques for deriving estimates of recent fertility from simple questions in censuses and surveys is the 'P/F ratio' method. Availability of detailed birth-history data, as in the World Fertility Survey, and applications of the P/F procedure as a diagnostic tool in the evaluation of the quality of data have led to simplifications and extensions of the original method. This analysis illustrates that when complete maternity histories are available, the P/F procedure can be simplified and made more powerful by (1) calculation of P/F values from cohort-period fertility rates and (2) use of two further indexing variables, namely duration since first marriage and duration since first birth, in addition to age. More generally, the paper indicates that a set of P/F values is only one of a battery of measures which aid in the analysis of trends and errors in data from maternity histories. Illustrative examples are given from various analyses of world Fertility Survey data. Howard Goldberg has been independently pursuing an investigation of the P/F procedure by marriage duration at the Office of Population Research (Princeton University), and we have profited from recent discussions with him. We would also like to acknowledge useful comments and criticisms on earlier drafts from James Trussell and Kenneth Hill.     

Using Retrospective Surveys for Estimating the Effects of Breastfeeding and Childspacing on Infant and Child Mortality

Recent contributions to our knowledge about the effects of breastfeeding and pace of childbearing on early child mortality have originated in the analysis of birth histories elicited from retrospective interviews. The validity of these findings has been questioned on the ground that when the timing of events is systematically distorted, estimates of effects will be affected by serious biases. In addition, it has been argued that the results obtained are highly sensitive to the models used and the techniques of estimation applied to calculate estimates of effects. In this paper we review the most important criticisms levelled against recent findings and interpretations and show that they rest on propositions of questionable validity.     

Nonreporting of births or nonreporting of pregnancies? Some evidence from four rural counties in North China

Coale and Banister argue that in China, elevated sex ratios in retrospective surveys are in part a function of collecting birth histories in a culture in which the definition of a birth may exclude mortality shortly after birth: an infant death in the West may be a stillbirth in east Asia. I present data from a recent sample survey featuring a retrospective pregnancy history. These data reveal that at least in the first pregnancy, from which the preponderance of sample births arise, there is no evidence of elevated female infant mortality or of high numbers of stillbirths, but that reported sex ratios are unusually high. The proportion of stillbirths grows for later pregnancies, but not enough to account for high sex ratios. Retrospective fertility data regarding recall over a recent interval are vexed less by a misunderstanding of what a live birth is than by a “misunderstanding” of what a (reportable) pregnancy is.     

Invisible or Mainstream? Disability in Surveys and Censuses in Low- and Middle-Income Countries

Social Indicators Research - This paper examines to what extent household surveys and censuses in low- and middle-income countries include disability questions and the types of questions under use....