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Biomedical subjects

G S Littman

Publications and source records attributed to G S Littman.

3 recordsLinked to original sources

Robustness of life table methods in large populations--a study by computer simulation.

The robustness of the product life table estimator of the survival function was studied for large populations under perturbations in the age distribution, changing levels of mortality and changing patterns of fertility. A macrosimulation system, based on a class of stochastic population models called generalised age-dependent branching processes, was used to carry out the numerical investigations. Aside from drastic perturbations in the age distribution and changes in levels of mortality, the product life table estimator of the survival function was found to be robust in large populations, under a variety of conditions.

Age Factors

Methodological issues underlying multiple decrement life table analysis.

In this paper, the actuarial method of multiple decrement life table analysis of censored, longitudinal data is examined. The discussion is organized in terms of the first segment of usage of an intrauterine device. Weaknesses of the actuarial approach are pointed out, and an alternative approach, based on the classical model of competing risks, is proposed. Finally, the actuarial and the alternative method of analyzing censored data are compared, using data from the Taichung Medical Study on Intrauterine Devices.

Female

Implications of fertility patterns in the Republic of Korea: a study by computer simulation.

Implications of various fertility patterns in the Republic of Korea (ROK) are studied by computer simulation. These patterns include the factors: age of marriage, sex preference, abortion (induced), contraception and sterilisation. As a result of studying a large number of combinations of these factors, the following tentative conclusions, among others, are reached. If future cohorts of women in the ROK become limiters after two live births and marry according to an observed high level marriage distribution, at least two of the methods of birth control--abortion, contraception, and sterilisation--will have to be used extensively to yield a mean number of live births (MNLB) in these cohorts of the order 2-2. However, if these women marry later than the observed high level marriage distribution and, in addition, accept effective methods of contraception more widely and use them more effectively, then the MNLB experienced by these cohorts could move below 2-5 wihtout the extensive utilisation of abortion and sterilisation.

Abortion, Induced