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This paper develops two models, each of which is designed to estimate the probability of surviving from birth to selected exact ages of early childhood: namely ages two, three and five. The models are designed for use in areas with deficient registration systems. They require, as input, statistics which can be derived from retrospective data supplied by census or survey respondents. The first model, the age model, converts statistics on the proportion dead of children ever born to women in age groups 20-24, 25-29 and 30-34 into estimates of q2, q3 and q5. The second model, the marriage model, converts statistics on the proportion dead of children ever born to women of five-year marriage duration intervals into these estimates. The models can be used independently or simultaneously. These models were developed from data generated by a large number of empirical fertility and mortality schedules. Regression analysis was used to determine the parameter values of the relationships specified, and several sets of equations for estimating values of qa for a =2, 3 and 5 comprise the final product of the paper. It should be noted that the conceptual basis for the models was first derived by William Brass. The data generated for the regression analysis provided an opportunity to test the original Brass estimated model. We are able to report that the model performed well over the wide range of fertility and mortality conditions included in the test. [ABSTRACT FROM AUTHOR]

The article presents a model for birth projections that contains birth probabilities for women, using age, cohort, and number of previous births as its essential parameters and including additional parameters that are psychological, economic, and sociological in origin. The article has three parts. First, the rationale is given for selecting these birth probabilities as the essential parameters. Second, the general procedure for estimating these parameters is given; this will involve the introduction of new parameters, both biological and social. Third, the general procedure will be illustrated in certain simplified special cases. In the course of the article, a number of relationships have very poor empirical estimates. From this perspective, one could argue that the article defines a program of research upon birth projections rather than a finished produce. From various cumulative distributions the author obtains cumulative births by multiplying the number of persons in each sample category by the number of children associated with that category save for the 7-and-up category that requires a special procedure.