Indirect Estimation Techniques Research Articles

Factors influencing child mortality in Bangladesh and their implications for the national health programme

"This study attempts to estimate by indirect estimation technique the levels of infant and child mortality in Bangladesh using the 1989 Bangladesh Fertility Survey (BFS). The levels of infant and child mortality obtained from the 1989 BFS indicate substantial improvements in child survival, although the fall in infant mortality has been faster than the fall in child mortality."

Estimating maternal mortality by sisterhood method in rural Zimbabwe.

The maternal mortality ratio (maternal deaths per 100,000 live births) is a good indicator of development and is influenced by basic health status, socioeconomic factors, health care and transportation, cultural and religious beliefs, level of education, and reproduction behavior. Estimation can be expensive, time consuming, and labor intensive. In Zimbabwe, maternal mortality has shown variation from 51/100,000 from a Harare hospital study in 1981 to 168/100,000 in a community-based incident case study in Masvingo province in 1991. This article describes an indirect estimation technique for estimating maternal mortality levels from sisters' data in Gutu District, Masvingo province, Zimbabwe. Data were obtained from community residents on the deaths of sisters during pregnancy, childbirth, or 42 days after termination of pregnancy. Data was collected during June-July, 1991, from all residents in a 5 km catchment area of 6 rural health centers and a residential area of the city of Mpandawana. Respondents were 37.3% male and 62.7% female. Survey results indicate 31.6 maternal deaths per year in the district. Unpublished observations from recorded deaths in heath centers, hospitals, and referral hospitals was estimated for the district over the past 4 years as 5.5. The suggestion is that institutional records are not representing 25% to 58% of total maternal mortality. These missed deaths occur in home-based deliveries by traditional birth attendants and reflect complications of pregnancy not referred to hospitals. Concern is raised about the preference for home delivery and the need for increased coverage of prenatal care and institutional deliveries. Future studies might include questioning traditional birth attendants about maternal deaths.

A Note on Quantile Estimation for Curtailed Experiments

AbstractThere may be experiments where due to misadventure or logistic or ethical reasons final measurements on all experimental units cannot be obtained. If at least 50% of the final measurements have been taken estimates of the lower quantiles and the median can be obtained. For such curtailed experiments it is shown how quantiles, above those that can be estimated directly from the data set, can be estimated indirectly by exploiting a property of symmetric distributions. The performance of the indirect quantile estimator is compared with that of the direct quantile estimator and conditions for the indirect estimator to have smaller variance than the direct estimator are presented. It is also shown how the indirect estimator may be pooled with the direct estimator to obtain an improved estimate of the upper quantiles.When it cannot be assumed that the data come from a symmetric distribution transformations to symmetry may be performed and the indirect estimation technique used on the transformed data; back transformations then yield the estimates of the upper quantiles.

Population projections for Myanmar, 1983-2013

A researcher used 1973 and 1983 census data to examine various demographic factors which affect population growth, to forecast the future size of the population, and to examine socioeconomic effects of rapid population growth on Myanmar. The researcher had to adjust 1983 data since remote rural areas were not included in the census. Since data quality was flawed, indirect estimation techniques were used to estimate fertility, mortality, and life expectancy at birth. The researcher used the UN general assumption model to make 9 populations projections. The medium variant showed that the population would increase from 35,442,972-64,504,980 between 1983-2013 at an annual rate of 2.02%. For the low and medium variants, the percentage of the population 15 years old would fall from 38.75% to 28.84% and 29.53% respectively between 1983-2013. The low variant projection showed an increase to 40.95%. The dependency ratio was highest in 1973 (.87), but fell to .82 by 1983. The low and high variant projections showed the dependency ratios to remain high until 1998, then they would steadily fall to .56 and .58 by 2013. The high variant projection revealed a slight rise throughout the 30 year period with the dependency ratio peaking in 2003. Rapid population growth in Myanmar reduced the availability of land. Between 1974 and 1990, sown area under various crops increased only 8% while population grew 22%. In terms of health, Myanmar would need an increased number of physicians and nurses at all variants in 2013 if the ratio of health personnel to population could be held constant (2.2 and 1.6 respectively). At the high variant, the numbers would need to more than double (8381-17,739 and 5335-12,974 respectively) to at least maintain 1983 services. The number of teachers who be needed in 2013 would also need to increase more than 2 times the 1983 number at the high variant projection if the ratio of teachers to students could be held at 1:39 (134, 116-341, 367). Therefore Myanmar needs family planning to effect socioeconomic development.

Conditional regression analysis

This article deals with the question of whether the inclusion of multiplicative terms to model conditional effects in multiple regression is legitimate. The major arguments in the controversy relating to this subject are reviewed. The main conclusion is that most of the objections against multiplicative terms are based on misinterpretations of the coefficients of conditional models. For the often-ignored possible numerical problems in the estimation of these models, due to multicollinearity, an indirect estimation technique is proposed. The potentials of conditional regression analysis are demonstrated on a concrete example.

Intercensal Change and the Indirect Estimation of Mortality: The Case of Pakistan

"In a country such as Pakistan, where there is no vital registration system, estimating mortality levels and trends can be difficult. One way we can learn about mortality is to use indirect estimation techniques on census age distributions. This paper applies some of these techniques and evaluates the quality of the census data in the process." Problems of relative coverage in the 1972 and 1981 censuses and changes in age-reporting preferences are discussed. Comments by Mohammad Afzal are included (pp. 583-5).

The Indirect Estimation of Migration: A Critical Review

Indirect estimation techniques for measuring emigration were first proposed by members of the IUSSP Working Group for the Study of International Migration, as a complement to methods based on more traditional types of data such as place of birth, place and duration of residence, and date of arrival. 2 approaches were suggested: 1, based on obtaining information from mothers on the place of residence of their children, was proposed by Somoza; the other, which requires all respondents to furnish information about the place of residence of their brothers and sisters, was developed by Hill. The aim of both methods is to obtain an estimate of the total number, and distribution by age and sex, of persons born in 1 country, but residing in another. The residence of children method has now been tried in at least 10 different censuses and surveys, mainly in Latin America and the Caribbean, and the analysis of these data allows assessment of the methods' strengths and weaknesses with some confidence. The residence of sibling technique has not been used as widely, so that, in spite of its theoretical attractions, its performance in the field cannot be evaluated to the same extent. This article seeks to summarize the methodology and to examine some recent theoretical developments. In particular, an assessment is presented of biases in the estimates of emigration obtained by the indirect methods. 3 main sources of error have been identified: reporting errors arising during fieldwork, estimation errors arising in the course of analysis through the use of biased inputs, and errors due to the use of age distributions of relatives derived from model stable populations.

Demography of the Juang tribal population of Orissa.

Demographic analysis of genealogical data collected in 1954 for 23 Juang villages was undertaken employing indirect estimation techniques and computer projection methodology. Results indicated that this group did not feature the historically high fertility levels associated with Indian tribal groups, although fertility was higher than previously reported for the Juang. The population did feature a mortality differential, with worse mortality conditions than the Indian national population at this time. Reversed sexual mortality differentials, common in South Asian populations, were also present for the Juang. Computer projection investigation revealed a steadily growing population, in contrast to some Indian tribal groups faced with extinction.

An analysis of indirect mortality estimation

Abstract In this paper the robustness of Brass's child-survivorship indirect mortality estimation technique is investigated. An analytical method is developed for studying the error or bias caused in indirect mortality estimates by poor data, badly chosen model functions, and specific demographic assumptions that are often violated in practice. The resulting analytical expressions give insight into the rationale of indirect methods, the conditions under which they are robust, and the magnitude of errors that occur when specific assumptions are violated.

Indirect measurement of the mean acoustic backscattering cross section of fish

A technique is described for indirectly determining the average backscattering cross section of individual fish from the measured probability distribution function for the amplitudes of the envelopes of single fish echoes. The technique is based on the assumption that the on-axis echo envelope is Rayleigh distributed. The validity of the Rayleigh assumption was tested by making controlled measurements of the envelope amplitude statistics of single fish echoes for two acoustic frequencies and four different fish lengths. These tests showed that the echo envelope data most closely fit the Rayleigh model when the ratio of fish length to wavelength was large. The indirect measurement technique described has been used to analyze some single fish-echo amplitude data for Bering Sea walleye pollock. These results are compared with some measurements made using a dual beam, direct, target strength measurement system. Expressions for the bias and variance of the indirect estimation technique are derived in an Appendix.

Evaluation of Double-Sampling Estimators of Subalpine Herbage Production

Electronic capacitance metering, relative and dry weight estimations, and canopy cover estimation of herbaceous standing crops were statistically evaluated with respect to sampling costs, precisions, and the vegetal and environmental factors which affected their double-sampling correlations. Twenty-four factors were investigated using stepwise regression analysis. Minimum sampling costs were achieved when the double-sampling estimator technique was compatible with the characteristics of the sampling site. Relative and dry weight estimations were found to be consistently precise estimators in meadow, aspen, fir, and spruce-flr, and spruce-fir vegetation types. Both were successfully used by workers with no prior experience or training. The sampling techniques were capable of providing, at equal sampling cost, up to a 4-fold increase in sample size over that of clipping along, depending on the vegetation type. The need for an inexpensive and precise estimator of herbage yield has become a classic topic in the range literature. A great deal of attention has been paid to the subject, primarily because of the difficulty in adequately sampling the highly variable standing crops encountered in many vegetation types. Since harvesting herbage is expensive and destructive, a technique which uses a large sample of acceptably lower precision estimates is generally better than a small sample of precise clipped measurements. The statistical parameters obtained with an estimator, however, must not be biased (Haydock and Shaw 1975) and the sample must also be less expensive to obtain than clipping, at equal levels of precision (Green 1949). A variety of both direct and indirect estimation techniques have been proposed which use a doublesampling with regression procedure (Cochran 1977) to minimize bias. While most of the techniques have been tested in the field, an uncertainty in how they compare with respect to cost, precision, and the factors influencing their performance, h,ave made it difficult to choose the most efficient technique in a given sampling situation. The need for analysis of the factors influencing the precision of various double-sampling estimators has been recognized by several authors (Morley et al. 1964; Bryant et al. 1971; and Michalk and Herbert 1977). Jones et al. (1977) recently investigated the effects of tropical grassland composition on The authors are former graduate research assistant, former research technician and professor, respectively, Department of Range Science, Utah State University, Logan, UJtah 84322. Reese is now ecologist, Division of Energy, Missouri Department of Natural Resources, Jefferson City. Bayn is now research technician, Department of Biology, Utah State University. This research was supported by National Science Foundation Grant DEB 75-13966 to James A. MacMahon and Utah Agr. Exp. Sta. Project 766. Submitted as Utah Agr. Exp. Sta. Journal Paper 2272. The authors wish to thank Mr. K.P. Haydock, C.S.I.R.O., Div. of Mathematics and Statistics, Cunningham Laboratory, St. Lucia, Queensland and Dr. Walter F. Mueggler, U.S.D.A., Forest Serv., Forestry Sciences Laboratory, Logan, UJtah, for their critical comments on the manuscript. Debbie Ketchie, Susan Kadlec, and Marilyn Pratt assisted with field work. electronic capacitance metering. However, similar regression studies on other double-sampling estimators are